Add mobile services, web proxy, and Gemma4 agent loop

- Mobile: add push notification and calendar sync services with full test suite (calendar, eventStore, notifications,
  screens)
- Mobile: add EAS build config and Jest setup
- Web: add API proxy, update useDestinationStation/useJourneys hooks, add middleware tests
- Web: update next.config and rebuild
- Agent: add Gemma4-based agent loop (agent_base, ttl_agent, ts_agent)
- Docs: add privacy policy, post-MVP plan, and aider rules

packages/api-client/src/client.ts

@@ -74,6 +74,20 @@ export class ApiClient {
     return res.json();
   }
 
+  /**
+   * Send an arbitrary HAFAS protocol body to the /api/hafas endpoint.
+   * This handles TripSearch, LocMatch, and any other HAFAS methods.
+   */
+  async hafasRequest<T = Record<string, unknown>>(body: unknown): Promise<T> {
+    const res = await fetch(`${this.baseUrl}/api/hafas`, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(body),
+    });
+    if (!res.ok) throw new Error(`HAFAS request failed: ${res.status}`);
+    return res.json();
+  }
+
   async searchJourneys(
     fromStationExtId: string,
     toStationExtId: string,