fix: run Rust tests in CI (#671)

* fix: run Rust tests in CI

Fixes #670

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: run Rust tests in CI

Adds a separate test.yml workflow to run existing Rust unit tests.

Fixes #670

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* refactor: use mock TranscriptionManager in CI tests

Swap to a mock adapter during CI to avoid compiling whisper/Vulkan.
The mock has the same interface but no heavy dependencies.
Existing tests don't exercise transcription code, so this is safe.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/test.yml

@@ -0,0 +1,24 @@
+name: "test"
+on: [pull_request]
+
+jobs:
+  rust-tests:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libwebkit2gtk-4.1-dev libappindicator3-dev librsvg2-dev libasound2-dev libssl-dev
+
+      - name: Use mock TranscriptionManager (CI only)
+        working-directory: src-tauri
+        run: |
+          # Swap to mock adapter - avoids compiling whisper/Vulkan
+          cp src/managers/transcription_mock.rs src/managers/transcription.rs
+          sed -i '/^transcribe-rs/d' Cargo.toml
+
+      - name: Run Rust tests
+        working-directory: src-tauri
+        run: cargo test

src-tauri/src/managers/transcription_mock.rs

@@ -0,0 +1,55 @@
+// CI-only mock TranscriptionManager - avoids whisper/Vulkan dependencies.
+// This file is copied over transcription.rs during CI tests.
+// Existing tests don't exercise transcription, so this is safe.
+
+use crate::managers::model::ModelManager;
+use anyhow::Result;
+use serde::Serialize;
+use std::sync::Arc;
+use tauri::AppHandle;
+
+#[derive(Clone, Debug, Serialize)]
+pub struct ModelStateEvent {
+    pub event_type: String,
+    pub model_id: Option<String>,
+    pub model_name: Option<String>,
+    pub error: Option<String>,
+}
+
+#[derive(Clone)]
+pub struct TranscriptionManager {
+    #[allow(dead_code)]
+    app_handle: AppHandle,
+}
+
+impl TranscriptionManager {
+    pub fn new(app_handle: &AppHandle, _model_manager: Arc<ModelManager>) -> Result<Self> {
+        Ok(Self {
+            app_handle: app_handle.clone(),
+        })
+    }
+
+    pub fn is_model_loaded(&self) -> bool {
+        false
+    }
+
+    pub fn unload_model(&self) -> Result<()> {
+        Ok(())
+    }
+
+    pub fn maybe_unload_immediately(&self, _context: &str) {}
+
+    pub fn load_model(&self, _model_id: &str) -> Result<()> {
+        Ok(())
+    }
+
+    pub fn initiate_model_load(&self) {}
+
+    pub fn get_current_model(&self) -> Option<String> {
+        None
+    }
+
+    pub fn transcribe(&self, _audio: Vec<f32>) -> Result<String> {
+        Ok(String::new())
+    }
+}