v2.0.5: Fix E2E flow - proxy, welcome screen, provider sync

Critical fixes:
- Translation proxy now uses system Node.js (not Electron binary)
- Removed duplicate proxy start causing port conflicts
- Added port availability check before spawning proxy
- Fixed welcome:choice double resolve()
- Fixed settings.html close using deprecated remote
- Fixed translationProxy /v1 for openai-compat backends
- Proxy no longer detached/unref - properly tracked as child
- SingletonLock cleanup on startup

Verified E2E:
- Welcome screen on first run ✓
- Provider selection works ✓
- Settings save + sync ✓
- Translation proxy starts correctly ✓
- LS connects to proxy ✓
- --ag-reset works ✓

dist/main.js

@@ -156,12 +156,9 @@ electron_1.app
     providerService = new providerService_1.ProviderService(storageManager);
     console.log(`[Provider] Active provider: ${providerService.getActiveProvider()}`);
 
-    // Start API proxy if a non-Gemini provider is active
-    if (providerService.needsProxy()) {
-        apiProxy = new apiProxy_1.ApiProxy(providerService);
-        apiProxy.start();
-        console.log(`[Provider] API proxy started for ${providerService.getActiveProvider()}`);
-    }
+    // NOTE: Translation proxy is now started by ensureProxyStarted() in languageServer.js
+    // which reads ~/.codex/endpoints.json (synced by syncProviderToEndpoints) and spawns
+    // the Node.js translation proxy on port 48080. No duplicate proxy needed here.
 
     // Handle deep link URL from command line arguments (All platforms)
     const deepLinkFromArg = process.argv.find((arg) => arg.startsWith('ag-x://'));
@@ -469,6 +466,7 @@ function showWelcomeScreen(mainUrl) {
                 } catch(e) { console.error('[Welcome] Failed to set Google endpoint:', e); }
                 welcomeWin.close();
                 // Don't createWindow here — LS hasn't started yet, main window opens after LS starts
+                return; // Don't fall through to resolve() again
             } else {
                 console.log('[Welcome] User chose custom provider — opening settings');
                 welcomeWin.close();