feat: Gemini AI integration — conversations, messages, image gen

- Fixed YAML parse error (unquoted colon in description broke @scalar/json-magic)
- Converted orval.config.ts → orval.config.cjs (fixes orval v8 TypeScript config loading)
- Codegen now works: zod schemas + React Query hooks regenerated with Gemini types
- Added Gemini tag, 4 path groups, 8 schemas to openapi.yaml
- lib/integrations-gemini-ai wired: tsconfig refs, api-server package.json dep
- Created routes/gemini.ts: CRUD conversations/messages + SSE chat stream + image gen
- Mounted /gemini router in routes/index.ts

artifacts/api-server/src/routes/index.ts

@@ -16,6 +16,7 @@ import estimateRouter from "./estimate.js";
 import relayRouter from "./relay.js";
 import adminRelayRouter from "./admin-relay.js";
 import adminRelayQueueRouter from "./admin-relay-queue.js";
+import geminiRouter from "./gemini.js";
 
 const router: IRouter = Router();
 
@@ -30,6 +31,7 @@ router.use(relayRouter);
 router.use(adminRelayRouter);
 router.use(adminRelayQueueRouter);
 router.use(demoRouter);
+router.use("/gemini", geminiRouter);
 router.use(testkitRouter);
 router.use(uiRouter);
 router.use(nodeDiagnosticsRouter);