feat: Add OpenAI-compatible provider nodes

- Support multiple OpenAI-compatible providers with custom prefix/baseUrl
- Add provider nodes CRUD (create/read/update/delete)
- URL building: baseUrl + /chat/completions or /responses
- Model import from /models endpoint
- API key validation via /models
- Usage type safety across all translators
- OAuth token auto-refresh for expired tokens

src/app/api/providers/[id]/route.js

@@ -32,7 +32,7 @@ export async function PUT(request, { params }) {
   try {
     const { id } = await params;
     const body = await request.json();
-    const { name, priority, globalPriority, defaultModel, isActive, apiKey } = body;
+    const { name, priority, globalPriority, defaultModel, isActive, apiKey, testStatus, lastError, lastErrorAt } = body;
 
     const existing = await getProviderConnectionById(id);
     if (!existing) {
@@ -46,6 +46,9 @@ export async function PUT(request, { params }) {
     if (defaultModel !== undefined) updateData.defaultModel = defaultModel;
     if (isActive !== undefined) updateData.isActive = isActive;
     if (apiKey && existing.authType === "apikey") updateData.apiKey = apiKey;
+    if (testStatus !== undefined) updateData.testStatus = testStatus;
+    if (lastError !== undefined) updateData.lastError = lastError;
+    if (lastErrorAt !== undefined) updateData.lastErrorAt = lastErrorAt;
 
     const updated = await updateProviderConnection(id, updateData);