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/routes/transcript-debug.ts

@@ -105,11 +105,14 @@ export function handleTranscriptDebugRaw(sessionId: string, url: URL): Response
     return errorResponse(`Session ${sessionId} not found`, 404)
   }
 
+  const stat = statSync(filePath)
   const content = readFileSync(filePath, 'utf-8')
   return new Response(content, {
     status: 200,
     headers: {
       'Content-Type': 'text/plain; charset=utf-8',
+      'Content-Length': String(stat.size),
+      'X-File-Size': String(stat.size),
       ...corsHeaders
     }
   })