fix(desktop): corrige permissoes e redimensionamento do chat

- Adiciona chat-hub explicitamente nas capabilities do Tauri
- Adiciona .resizable(false) nas janelas de chat e hub
- Corrige problema de comandos invoke nao funcionando no hub

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/desktop/src-tauri/capabilities/default.json

@@ -2,7 +2,7 @@
   "$schema": "../gen/schemas/desktop-schema.json",
   "identifier": "default",
   "description": "Capability for all windows",
-  "windows": ["main", "chat-*"],
+  "windows": ["main", "chat-*", "chat-hub"],
   "permissions": [
     "core:default",
     "core:event:default",