chore(tauri): remove dead code warnings and drop unused uuid dep

- Delete unused Provider::new, ProviderManager::get_current_provider
- Delete unused AppState::reload
- Remove uuid crate and related imports
- Keep functionality unchanged; frontend uses ID string for current provider

src-tauri/capabilities/default.json

@@ -8,7 +8,6 @@
   "permissions": [
     "core:default",
     "shell:allow-open",
-    "shell:allow-execute",
     "opener:default"
   ]
-}
+}