v0.1.2

Highlights:

- Denser main UI: smaller header/search area and tighter footer action spacing.

- Cleaner history rows: removed right-side metadata clutter from the list.

- Search behavior remains instant and full-text; details stay in preview panel.

- README refreshed for current search architecture and packaging examples.

- App version bumped to 0.1.2 in Tauri/Cargo metadata.

fix: position window near cursor on show

- Horizontally center window on cursor X position, clamped to monitor edges
- Vertically center on the monitor containing the cursor
- Properly handle multi-monitor setups by detecting which monitor has the cursor
- Linux: uses xdotool getmouselocation for cursor position
- macOS: uses NSEvent mouseLocation via osascript
- Window is positioned before show() to avoid visual jump

feat: add launch at startup setting

- Add launch_at_startup field to AppConfig (default: false)
- Add autostart module with platform-specific support:
  - Linux: creates/removes ~/.config/autostart/paw.desktop
  - macOS: creates/removes ~/Library/LaunchAgents/com.paw.app.plist
            and calls launchctl load/unload
- Apply autostart change automatically when config is saved
- Add 'Launch at system startup' toggle in Settings > General

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>