Eliminate the showAllDeepInfraModels runtime/admin config and all code paths
that allowed restricting Deepinfra's model catalog. Deepinfra now always
shows the full model list regardless of API key or environment variable.
Update documentation, environment examples, admin panels, runtime config,
provider catalog logic, and tests to reflect this change.
Remove fallbackProviderRef usage from settings and config context to streamline
provider resolution. Adjust normalizeLegacyProviderRef to retain 'default-openai'
unless a non-default fallback is explicitly provided. Update provider listing to
enforce deterministic ordering by updatedAt, createdAt, and slug. Expand unit tests
to verify provider ordering, legacy ref normalization, and selection logic.
Transition all TTS-related logic, types, and UI to use the new providerRef/providerType model in place of legacy ttsProvider fields. Introduce a centralized tts-provider-policy module to encapsulate provider/model capability checks, default value resolution, and compatibility logic. Update all API routes, contexts, hooks, components, and tests to use providerRef and providerType, ensuring consistent handling of built-in and shared TTS providers. Remove legacy defaultTtsModel config in favor of per-provider defaults and shared provider admin control. Add the showAllProviderModels runtime flag to restrict users to provider default models when desired.
BREAKING CHANGE: ttsProvider fields are replaced by providerRef/providerType throughout the codebase; defaultTtsModel config is removed in favor of per-provider defaults.
Add database-backed runtime configuration for feature flags and TTS provider credentials, editable via a new admin UI panel. Replace static NEXT_PUBLIC_* and TTS provider env vars with admin-managed settings stored in the database and injected at SSR for client access. Implement admin-only panels for managing shared TTS provider credentials (with encrypted API keys) and live site feature flags. Add schema migrations, API routes, React contexts, and hooks for SSR-injected runtime config and live updates. Update client and server logic to resolve configuration from the database at runtime, enforcing admin restrictions and supporting migration from legacy env-based config.
BREAKING CHANGE: Feature flags and TTS provider credentials are now managed at runtime via the admin UI. Environment variables are only used for initial seeding and are ignored after first boot. Existing deployments must migrate configuration to the admin panel.
Eliminate the deprecated `/api/tts` route and its client usage, consolidating TTS generation logic under chapter and segment endpoints. Update client API utilities to remove direct TTS buffer fetching and improve error propagation for chapter generation failures. Extend TTS segment error metadata to include upstream rate limit and retry details, and standardize error typing in shared types. Adjust tests and helpers to reflect the new TTS mocking approach and endpoint structure. This streamlines TTS API surface and enhances error reporting consistency.
Move daily quota exceeded problem response logic to a dedicated utility in `lib/server/rate-limit/problem-response`. Refactor API routes to use the new builder and remove duplicated formatting code. Update all relevant imports for consistency. This improves maintainability and ensures uniform error responses across TTS endpoints.
Move `epub-word-highlight`, `tts-epub-handoff`, and `tts-epub-preload` from shared to client/epub to clarify their usage and improve bundling. Update all imports to use new client paths. Extend TTS and sidebar logic to support HTML document progress tracking and restoration, introducing a new location format for HTML and consistent handling for non-EPUB readers.
BREAKING CHANGE: EPUB TTS utilities relocated to `lib/client/epub`; update import paths. HTML progress persistence now uses a new format incompatible with previous versions.
Redesign TTS segment storage by decomposing the `tts_segments` table into two normalized tables: `tts_segment_entries` for unique segment identity and locator projection, and `tts_segment_variants` for per-settings audio variants. Update schema, queries, and API routes to use the new structure, including manifest pagination and segment resolution logic. Refactor segment locator handling to use stable projections and manifest cursors. Migrate tests and data cleanup utilities to support the new model.
BREAKING CHANGE: Database schema for TTS segments is now split into entry and variant tables; all code and consumers must use the new structure. Persisted data and APIs relying on the old `tts_segments` table are incompatible.
Implement strict validation for EPUB TTS segment locators, requiring stable spine coordinates (`spineHref`, `spineIndex`, `charOffset`) and rejecting legacy CFI-only locators. Introduce `segmentKey` as a normalized identity derived from segment text, used for robust merging and deduplication of synthesized and persisted segments. Update database schemas, API routes, and manifest logic to support the new locator format and segmentKey. Add helpers for locator resolution and segmentKey construction, with comprehensive unit tests for identity, normalization, and manifest grouping.
BREAKING CHANGE: Persisted EPUB TTS segment locators must now include stable spine coordinates; legacy CFI-only locators are no longer accepted. Consumers must handle the new `segmentKey` field for segment identity and merging.
Refactor TTS segment identification to support canonical segment keys, decoupling segment IDs from locator and index for more robust deduplication and handoff. Add `segmentKey` to segment types, manifest, and ensure route. Implement natural sorting for EPUB CFI locations and segment locators using new comparison utilities. Update sidebar and manifest helpers to use locator-aware sorting. Add foundational modules for EPUB word highlighting, TTS segment planning, and EPUB handoff logic. Expand types and tests to cover new canonical segment and locator behaviors.
BREAKING CHANGE: TTS segment IDs now support canonical segment keys; APIs and manifest consumers must handle `segmentKey` and updated locator comparison logic.
Introduce configurable segment preloading depth, sentence lookahead, and TTS segment max block length for both PDF and EPUB readers. Add new settings to user preferences, config context, and document settings UI. Refactor TTS segment splitting logic to support per-user max block length and propagate these options through PDF/EPUB adapters and TTS segment generation. Update API, manifest pagination, and segment deduplication for improved performance and correctness. Add tests for new NLP options and manifest logic.
BREAKING CHANGE: TTS segment splitting and manifest APIs now require max block length and preloading parameters; user config schema updated.
Introduce SegmentsSidebar component and supporting reader UI for segment-level
navigation and inspection. Add TTS segments manifest and clear API endpoints to
enable efficient retrieval and management of segment variants. Update TTS
segment schema to include settings_hash for improved lookup and indexing,
and adjust indexes to use settings_hash instead of settings_json. Update
contexts and types to support segment variant display and interaction.
This enhances document navigation and TTS segment management for end users.
Remove legacy TTS segment manifest and audio endpoints in favor of new presigned and fallback audio URL approach. Update segment manifest structure to include `audioPresignUrl` and `audioFallbackUrl` fields, deprecating the previous `audioUrl`. Refactor segment ensure logic and TTS context to utilize the new playback source model. Add server utilities for generating presigned S3 URLs and introduce new API routes for presign and fallback audio retrieval. Clean up obsolete client API functions and types to reflect the new manifest format.
Introduce TTS segment support with new database tables and migrations for both Postgres and SQLite. Implement segment ensure, audio, and manifest API endpoints, segment storage in S3, and segment authorization logic. Update TTS context and client API to use segment-based synthesis and retrieval. Add server-side helpers for segment ID, settings hash, locator normalization, and audio probing. Extend user data cleanup and teardown logic to remove TTS segment objects. Add unit tests for segment helpers.
BREAKING CHANGE: TTS synthesis now uses segment-based storage and APIs; database migrations required.
Move resolveVoices and resolveReplicateVoiceInputKey to a new server-side
voice-resolution module to improve separation of concerns and reduce shared
bundle size. Update all imports and related tests to use the new module.
Remove unused LRUMap and related caches from shared catalog. Update Replicate
cooldown logic to use per-scope LRU cache for improved concurrency handling.
Move getUpstreamStatus and getUpstreamRetryAfterSeconds to a shared utility
module for consistent upstream error handling across TTS endpoints. Strengthen
audiobook chapter API by introducing runtime validation for incoming settings
payloads, ensuring type safety and error reporting for malformed requests.
Replace in-memory Map caches with LRUMap for Replicate voice and schema
lookups, improving memory management and eviction logic.
Align default Replicate model to the versioned Kokoro model across UI, docs,
and server logic. Refactor TTS settings merging for audiobooks to ensure
consistent normalization. Improve Retry-After header handling for upstream
rate limits. Expand Replicate voice resolution to use model schemas when
available, with test coverage for custom and built-in models.
Update documentation to reflect new Replicate defaults, model selection,
and configuration guidance.
- Updated environment variables documentation to include Replicate as a TTS provider option.
- Added Replicate to the sidebar for TTS provider guides.
- Included Replicate as a dependency in package.json and pnpm-lock.yaml.
- Enhanced audiobook chapter generation to normalize native speed settings based on the TTS provider.
- Improved error handling in TTS API routes to provide retry information for rate-limited responses.
- Updated AudiobookExportModal to reflect native speed support for Replicate models.
- Modified SettingsModal to set default model for Replicate.
- Enhanced SpeedControl component to conditionally render native speed controls based on provider support.
- Updated TTSContext to utilize effective native speed for TTS requests.
- Implemented Replicate request handling in the TTS generation logic.
- Added new documentation for configuring Replicate as a TTS provider.
Make voice-fetching more robust by always clearing the request timeout and stricter type-checking of remote data.
- move clearTimeout into finally blocks for Deepinfra and custom OpenAI voice fetches to guarantee the timeout is cleared on success, failure, or abort
- validate that custom endpoint returns an array of strings before accepting voices; otherwise fall back to defaults
This reduces potential timer leaks and avoids accepting malformed voice lists from custom endpoints.
Improve robustness across audiobook pipeline, TTS catalog, and preferences comparison.
- audiobooks: centralize abort creation with createAudiobookAbortError and replace repeated ad-hoc throws with it; avoid reprocessing non-completed chapters when collecting existing indices; update progress accounting by advancing processedLength and emitting onProgress after saving a chapter.
- tts: add a 10s AbortController timeout when fetching custom OpenAI voices, wire the signal to fetch, and ensure the timeout is cleared on success or failure; fall back cleanly when endpoint doesn't support voices.
- config: harden deepEqual by checking mismatched array vs object shapes early to avoid incorrect comparisons.
No user-visible behavior changes besides improved cancellation, progress reporting, and more resilient remote voice discovery.
- Move TTS provider resolution and voice-fetch logic into shared catalog and make
remote fetches more resilient (timeouts, abort handling, baseUrl normalization,
treat explicit empty custom-openai responses as valid).
- Add continuation guard to TTS feature set and update API voices endpoint error
logging to better surface auth/session failures.
- Extract and stabilize ebook pipeline and epub adapter:
- Cache prepared EPUB chapters to avoid repeated parsing and handle missing/empty
chapter titles safely.
- Fail early when created chapter lacks a bookId.
- Improve config/preferences handling:
- Replace JSON stringify comparisons with a deepEqual utility to compare defaults.
- Tighten ConfigContext effect dependencies and consolidate synced preference
queuing logic to include additional keys.
- Harden end-to-end test helpers and unit tests:
- Make settings dialog dismissal deterministic (use Enter/Escape and explicit
visibility/enabled checks) and simplify upload retry behavior.
- Add unit test to ensure custom-openai empty voice lists are preserved.
Why: Reduce runtime and test flakiness, centralize TTS logic for easier maintenance,
and make EPUB processing and preference diffing more robust. Breaking changes: none.
- Introduce a shared tts-provider-catalog to centralize provider/model/voice defaults
and feature flags (supportsTtsInstructions, providerSupportsCustomModel, resolveProviderModels,
getDefaultVoices, etc.). Replace ad-hoc provider logic across server and client with catalog calls.
- Replace inline voice/model UI logic in SettingsModal, AudiobookExportModal, TTSContext,
generate server code, and voice hook to use catalog helpers (resolveTtsSettingsViewModel,
supportsTtsInstructions, getDefaultVoices).
- Extract audiobook generation responsibilities into a small client-side pipeline:
- Add createEpubAudiobookSourceAdapter and createPdfAudiobookSourceAdapter adapter modules
to prepare chapters from EPUB/PDF sources.
- Add runAudiobookGeneration and regenerateAudiobookChapter pipeline functions to handle
chapter preparation, progress tracking, request header construction, and retry/abort behavior.
- Wire adapters/pipeline into EPUBContext and PDFContext to simplify and centralize audiobook flow.
- Move config preference helpers out of ConfigContext into dedicated client modules:
- buildSyncedPreferencePatch (lib/client/config/preferences.ts)
- applyConfigUpdate and getVoicePreferenceKey (lib/client/config/updates.ts)
- Use these helpers in ConfigContext to keep update logic small and testable.
- Add TTS settings view model resolver (lib/client/settings/tts-settings.ts) and tests
for the tts-provider catalog and config helpers (tests/unit/tts-provider-catalog.spec.ts).
- Minor usages updated: AudiobookExportModal, SettingsModal, useVoiceManagement, TTSContext,
server tts generation, and various context files to consume the new modules.
Why: Reduce duplication, improve testability, and separate concerns for provider metadata,
UI view-model logic, and audiobook generation flow. Breaking changes: none.
- Removed unused imports and types from TTS route.
- Consolidated TTS buffer generation logic into a new module.
- Implemented caching for TTS audio buffers using LRU cache.
- Updated TTS request handling to support instructions for specific models.
- Refactored audiobook chapter creation to use new TTS generation logic.
- Simplified error handling and response management in TTS API.
- Enhanced client-side logic to manage TTS requests and retries.
- Updated types to reflect changes in TTS request payload structure.
Add ZIP-based user data download endpoint, enable AES-256 server-side S3 encryption for all stored documents and audiobooks. Rewrite privacy policy with detailed CCPA categories, service provider disclosures (Vercel/Neon/Railway), and user rights sections. Replace privacy modal with checkbox agreement flow.
Add Next.js middleware to handle session-based access control for protected
routes while maintaining access to public paths. Configure comprehensive
security headers including CSP, HSTS, and frame options in next.config.ts.
Also, reduce session cookie cache duration to 5 minutes to ensure frequent
revalidation against the database and fix a navigation issue in the EPUB
context when jumping to specific CFI locations.
Move database drivers and heavy server-side modules to be loaded
lazily via require() and dynamic import(). This reduces the initial
memory footprint and improves cold start performance for serverless
functions by avoiding loading unused dependencies on every request.
Update the client-side preview status logic to gracefully handle failed
states and return fallback URLs. Add PDF worker tracing to the build
configuration for preview-related API endpoints and include server-side
error logging.
Implement a check for GitHub OAuth credentials to conditionally render
the GitHub sign-in button. This ensures the UI accurately reflects
available authentication methods based on environment configuration.
- Add `isGithubAuthEnabled` utility to verify server-side credentials
- Propagate GitHub auth status through context providers to the UI
- Conditionally display the GitHub sign-in button in the sign-in page
- Update documentation and examples to use hex encoding for `AUTH_SECRET`
- Add unit tests for the new GitHub authentication configuration logic
Implement AbortController in ConfigContext, PDFContext, and preference sync to prevent race conditions during session changes or rapid navigation. Refactor document preview routes into shared utilities and add LRU caching for text previews to optimize memory. Update documentation for Better Auth schema ownership and migration workflows. Fix issues with Postgres system user seeding and better-sqlite3 configuration.
- Implement ensureSystemUserExists to handle foreign key constraints for
unclaimed data when authentication is disabled.
- Add missing foreign key relationship between audiobook chapters and
audiobooks with cascade delete.
- Integrate a beforeDelete hook in auth config to trigger storage
cleanup when a user is removed.
- Regenerate initial migrations for both PostgreSQL and SQLite to
reflect schema updates.
- Updated SQLite journal metadata with new tag and timestamp.
- Refactored account deletion API to utilize Better Auth's built-in user deletion method for cascading cleanup.
- Enhanced database initialization to include authentication schemas for both SQLite and Postgres.
- Removed user, session, account, and verification tables from the Drizzle schema, as they are now managed by Better Auth.
- Created separate schema files for authentication in both Postgres and SQLite.
- Added SQL migration scripts for creating necessary tables in both database systems.
- Remove ffprobe-static dependency and associated configuration
- Reimplement ffprobeAudio to parse duration and title tags from ffmpeg output
- Update CI workflow to install SeaweedFS binary and set required environment variables
- Enhance E2E test setup to handle auth-protected endpoints during document cleanup
- Introduce `USE_ANONYMOUS_AUTH_SESSIONS` to make guest access an opt-in feature.
- Transition root-level pages into `(app)` and `(public)` route groups for improved access control.
- Adopt Figtree as the primary typeface and implement a pre-render theme initialization script.
- Decouple audiobook chapter processing into a standalone API route and harden resource ownership logic.
- Replace the legacy footer with a unified layout and add skeleton loading states for document lists.
- Update environment documentation and test suites to align with the revised routing and auth flows.
BREAKING CHANGE: The audiobook generation API has been restructured, moving specific chapter logic to `/api/audiobook/chapter`.
- Add document preview caching logic with in-memory and persisted storage.
- Implement S3 blobstore functions for managing document previews.
- Create rendering functions for PDF and EPUB cover images to JPEG format.
- Introduce database schema and functions for managing document preview metadata.
- Add unit tests for rendering PDF and EPUB previews.
- Implemented user preferences management with a new API for GET and PUT requests.
- Added user document progress tracking with a new API for retrieving and updating progress.
- Introduced database schema changes for user preferences and document progress.
- Enhanced EPUB and TTS contexts to support syncing user preferences and document progress.
- Added functions to handle transferring user preferences and progress during account linking.
- Updated client-side logic to schedule syncing of user preferences and document progress.
This commit restructures the audiobook generation and serving layer to rely exclusively on S3-compatible blob storage, removing the dependency on local filesystem paths.
- Bundle `ffmpeg` and `ffprobe` binaries via npm to ensure portability across environments.
- Update API routes to stream audio directly from blob storage instead of local disk.
- Remove legacy migration endpoints and filesystem-based indexing logic.
- Add startup scripts to facilitate the transition from local to remote storage.
BREAKING CHANGE: Audiobook functionality is now strictly dependent on S3 configuration. The previous filesystem-based storage method has been removed.
Add environment variables for fine-grained control over TTS rate limiting
and Better Auth behavior. Move documentation to external Docusaurus site
with automated deployment workflows.
- TTS rate limiting can now be enabled/disabled via TTS_ENABLE_RATE_LIMIT
- Customizable daily limits for anonymous/authenticated users and IP backstops
- Better Auth rate limiting can be disabled via DISABLE_AUTH_RATE_LIMIT
- Rename library import env vars to IMPORT_LIBRARY_DIRS/DIR
- Add docs-site with Docusaurus and GitHub Actions workflows
- Update README to reference external documentation
Replaces local filesystem document storage with S3-compatible object storage.
Adds embedded SeaweedFS 'weed mini' for local development and Docker deployments.
Updates document upload flow to use presigned URLs with a server fallback proxy.
Refactors auth configuration to use BASE_URL and AUTH_SECRET.
BREAKING CHANGE: Renamed BETTER_AUTH_URL to BASE_URL and BETTER_AUTH_SECRET to AUTH_SECRET. Removed legacy document upload/content endpoints. Requires S3 environment variables (auto-configured for embedded SeaweedFS).
- Replace client-side IndexedDB with server-first document storage
- Add document caching layer for offline capability and performance
- Implement document transfer during anonymous-to-authenticated account linking
- Add database indexes for improved query performance
- Update document contexts to use new caching system
- Refactor document upload and deletion APIs
- Add audiobook pruning for missing files
- Improve test isolation with namespace support
- Add unit tests for document cache and transfer functions
Ensure all metadata operations consistently use the database layer,
removing filesystem-only fallback paths and conditional DB checks.
- Simplified migration scripts to always run on startup
- Updated document/audiobook APIs to always query DB
- Added ensureDbIndexed() calls across all routes
- Extracted test namespace utilities to dedicated module
- Removed migration-manager.ts (functionality consolidated)
- Updated rate limiter to assume DB is always available
BREAKING CHANGE: Database is now required in all configurations.
When auth is disabled, SQLite is used by default at /app/docstore/sqlite3.db.
- Change audiobooks and audiobookChapters tables to use composite PK (id, userId)
- Migrate audiobooks from flat storage to user-specific directories under audiobooks_users
- Add support for claiming unclaimed audiobooks on account creation
- Improve auth rate limiting with retry logic and DISABLE_AUTH_RATE_LIMIT for tests
- Fix iOS/Safari audio playback with unlock mechanism and playback rate watchdog
- Update API routes to handle user-scoped audiobook access with fallback to unclaimed
- Transfer audiobooks when linking anonymous accounts to real accounts
- Remove foreign key constraint from audiobookChapters to support composite PK
- Add cascade delete to account and session foreign keys
Replace privacy popup with PrivacyModal and reorganize auth UI components
Remove signed-out persistence and centralize session handling in useAuthSession
Move document viewers and Kokoro voice helpers into dedicated modules
- Smooth react-pdf page turns with stable canvas staging and fade-in
- Retry transient empty page text extraction during fast page turns
- Avoid noisy TTS preload toasts, guard requests when quota is exhausted,
and improve Howler retry/unload behavior to prevent pool exhaustion
- Enforce auth FK cascade deletes and tighten rate-limiter bucket updates
using affected-row checks
- replace custom DB adapter with Drizzle setup (SQLite/Postgres schemas) and add `drizzle.config.ts` plus migrations in `drizzle/` and `drizzle_pg/`
- switch better-auth to drizzleAdapter, add auth helpers (`getAuthContext`, `requireAuthContext`, `requireAudiobookOwned`), and make `useAuth`/`useAuthSession` safe no-ops when auth is disabled
- persist documents/audiobooks in DB with ownership checks, unclaimed fallback, and ref-counted deletes; add FS scan helper for no-auth mode
- gate docx-to-pdf, library, voices, whisper, and migration endpoints behind auth when enabled
- add unclaimed data scan/claim flow with `/api/user/claim`, `ClaimDataModal`, and server-side scan/claim helpers
- refactor rate limiting and account deletion to use Drizzle tables (`user_tts_chars`, `user`)
- run migrations via `scripts/migrate-if-auth.mjs` (auto on `pnpm start` + `pnpm migrate`), remove Docker entrypoint and old better-auth migration file
- update README and lockfile for the new migration workflow and dependencies
- Add device ID and IP-based rate limiting to prevent abuse
- Refactor UI components for better header menus and settings
- Update privacy popup with detailed data usage info
- Improve PDF handling and caching to prevent react-pdf warnings
- Update README with new Docker instructions and environment variables
- Implement user sign-in, sign-up, and account management using better-auth
- Add rate limiting for TTS API with daily character limits for authenticated and anonymous users
- Integrate SQLite and PostgreSQL database support for user sessions and data persistence
- Update UI components to include authentication flows, user menu, and privacy popup
- Modify Dockerfile and package.json for new dependencies and entrypoint script
- Bump version to v1.3.0
- Add logic to split oversized sentences in `splitTextToTtsBlocksEPUB` using `splitOversizedText` to ensure blocks stay within `MAX_BLOCK_LENGTH`
- Remove `extractRawSentences` and `processTextWithMapping` functions as they are no longer needed
- Update tests to reflect the changes, including a new test for oversized sentence splitting and removal of related test suites
Introduce `splitTextToTtsBlocksEPUB` function to handle EPUB text splitting,
treating single newlines as paragraph boundaries for precise highlighting.
Update TTS context to conditionally use EPUB splitting based on document type.
Enhance PDFViewer to clear highlights when current sentence is null.
Add comprehensive tests for the new functionality and refactor existing ones.
- Rename and enhance text processing functions in nlp.ts for better handling of oversized texts, sentence boundaries, and PDF artifacts
- Update PDFViewer to add layout-aware highlighting with retry logic for sentence and word highlights
- Adjust PDFContext and TTSContext to use new normalized text functions
- Expand unit tests for new splitting behaviors, including long texts and punctuation preferences
- Introduces `DocumentPreview` component to display rich previews for documents.
- PDFs generate a thumbnail of their first page.
- EPUBs extract and display their cover image.
- HTML, TXT, and Markdown files show a text snippet.
- Refactors document list and folder views to a responsive grid layout.
- Expands main content areas to accommodate the new grid.
- Updates Dockerfile to use Node.js LTS image.
- Updates various development and runtime dependencies.
Abstracted direct fetch calls across components and contexts into new functions within `src/lib/client.ts`. This provides a consistent and centralized interface for interacting with backend APIs.
- Introduced `src/lib/client.ts` to encapsulate API request logic.
- Standardized audio buffer types (`TTSAudioBuffer`, `TTSAudioBytes`) in `src/types/tts.ts`.
- Moved client-specific request types (`TTSRequestPayload`, `TTSRequestHeaders`, `TTSRetryOptions`) to `src/types/client.ts`.
- Updated API routes and consumer components/contexts to leverage the new client library functions and type definitions.
- Removed `src/utils/audio.ts` as its utility functions are now part of `src/lib/client.ts`.
- Introduce `/api/whisper` endpoint which uses `whisper.cpp` (via a `WHISPER_CPP_BIN` executable) and `ffmpeg` to generate word-level audio alignments from provided audio and text.
- Integrate word-level alignments into `TTSContext`, tracking the currently spoken word based on audio seek position and provided timestamps. Alignments are cached in-memory and fetched asynchronously.
- Add new configuration options (`pdfWordHighlightEnabled`, `epubWordHighlightEnabled`) to `ConfigContext` and `Dexie` for enabling/disabling the feature.
- Implement visual word highlighting in both `PDFViewer` and `EPUBViewer` by mapping TTS-aligned words to rendered text elements.
- Enhance `EPUBContext` and `PDFContext` with new `highlightWordIndex` and `clearWordHighlights` functions, utilizing fuzzy string matching (`cmpstr`) to robustly align spoken words with displayed text for accurate highlighting.
- Update `DocumentSettings` to include user-facing toggles for the new highlighting modes.
- Reorganized utility modules from `src/utils` to `src/lib` for clearer separation of concerns.
- Introduced new, dedicated type definitions in `src/types` for improved type safety in configuration and TTS API interactions.
- Replaced `src/types/appConfig.ts` with `src/types/config.ts`.
- Added `src/types/tts.ts` for TTS request payloads, error structures, and retry options.
- Updated module imports across several contexts (`Config`, `EPUB`, `HTML`, `PDF`, `TTS`) and components to reflect the new `lib` and `types` locations.
- Enhanced TTS API request and error handling in `src/app/api/tts/route.ts` and TTS-consuming contexts with explicit types.
- Simplified `ProgressCard`, `ProgressPopup`, and `AudiobookExportModal` components by removing the `isProcessing` prop, centralizing processing state management.
- Streamlined `HTMLContext` by removing `createFullAudioBook` and `isAudioCombining` properties, focusing its scope.
