feat: integrate Claude binary and improve build workflow

- Add predev script to build executables before starting dev server
- Configure Tauri to include claude-code as external binary
- Reorganize Tauri command handlers with clear section comments for better maintainability
- Add bun build temporary files to .gitignore

These changes enable proper Claude binary integration and ensure executables are built before development.

Fixes #136

src-tauri/tauri.conf.json

@@ -57,6 +57,9 @@
       "icons/128x128@2x.png",
       "icons/icon.icns",
       "icons/icon.png"
+    ],
+    "externalBin": [
+      "binaries/claude-code"
     ]
   }
 }