feat: add system tray

[vishesh-sachan]

This Pull Request introduces complete system tray functionality to the Whispering application

1. System Tray Integration

• Full Desktop Integration: The application can now be minimized or closed to the system tray instead of quitting, allowing it to run silently in the background.
• Interactive Tray Menu: Includes standard "Show Whispering" to restore the window and a "Quit" option.
• Left-Click Behavior: A single left-click on the tray icon toggles the application window's visibility.

2. Dynamic State Indicators

The tray icon changes automatically to provide visual feedback on the app's current status:

• Idle: Default state when no activity is occurring.
• Recording: Indicates that a voice recording is actively in progress.
• Processing: Shows when a recording is being transcribed.
• Dynamic Tooltips: The icon tooltip updates (e.g., "Whispering - Recording") to further communicate the current state.

3. User Configuration

• A new System Tray section has been added to the Settings page.
• Minimize to Tray: A toggle to hide the window to the tray when the close button is clicked.
• Start Minimized: An option to launch the application directly to the system tray on startup.

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🛠️ Technical Details & Implementation

Backend (Rust/Tauri)

• New tray.rs module: Implements the entire tray management logic, including icon switching, menu setup, and event handling.
• Window Management: Intercepts the window close event to hide the window instead of quitting, respecting the user's closeToTray setting.
• State Management: Uses thread-safe state management (Arc<Mutex<>>) to handle tray state updates across different application threads (recording, transcription).
• New Commands: Introduced new Tauri commands for the frontend to manage and update the tray state in real-time.

Frontend (Svelte/TypeScript)

• Settings Schema/UI: Updated settings.ts and the Settings page UI to include the new tray configuration options.
• Recording Pipeline Integration: The application's recording and transcription services now dispatch updates to the backend to ensure the tray icon accurately reflects the Recording and Processing states.
• Reliability: Ensured robust state transitions across different recording methods (VAD, CPAL, etc.) and corrected timing issues in icon updates for a smoother user experience.

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📂 Files Impacted

• src-tauri/src/tray.rs (New)
• src-tauri/src/lib.rs (Tray setup and event handling)
• src/lib/settings/settings.ts (New tray settings schema)
• src/lib/stores/settings.svelte.ts (Settings store integration)
• src/routes/(config)/settings/+page.svelte (System Tray settings UI)
• ...and various files in src/lib/services and src/lib/query for state-change integration.