Extract release-based deploy triggers to new workflow for clarity and
reliability. Update docs-deploy.yml to streamline dispatch inputs and
remove release/workflow_run triggers. Extend build-changelog-feed.mjs to
support incremental changelog sync via workflow_dispatch with release tag
and action, enabling precise upserts and deletions of changelog entries.
Introduce changelog feed manifest support, including client and shared
utilities for fetching and parsing changelog data. Add a new
Settings modal panel for viewing changelog entries, with version
detection based on the current app version. Expose a configurable
changelog feed URL in both environment variables and admin panel
runtime settings. Update documentation and deployment workflow to
support changelog feed generation and consumption. Include unit tests
for changelog utilities.
