feat: enhanced AI usage logging (model, provider, response) and fixed build blockers

supa_schema.sql

@@ -238,6 +238,9 @@ CREATE TABLE IF NOT EXISTS api_usage (
     endpoint TEXT,
     success BOOLEAN DEFAULT true,
     error_message TEXT,
+    model TEXT,
+    provider TEXT,
+    response_text TEXT,
     created_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('Europe/Berlin'::text, now())
 );