feat: compact boundary divider, overlay fix, approval window, PiP, Tauri enhancements

- Add CompactBoundaryDivider component for compact_boundary system messages
- Fix readability overlay: v-if removes element entirely at 0% opacity
- Add approval page and window composable
- Add PiP window support and loading screen
- Tauri: add window management commands and capabilities
- Disable Ctrl+1..5 shortcuts in Tauri (handled by global shortcuts)

server/index.ts

@@ -7,6 +7,7 @@ initDatabase()
 
 // Start HTTP API server
 Bun.serve({
+  hostname: '0.0.0.0',
   port: PORT_HTTP,
   fetch: handleRequest
 })