feat(backend): add standalone data plane

Replace the Supabase application data plane with the Node/PostgreSQL API, migrate mobile, admin, web, and MCP callers, add controlled cutover tooling, and define hardened Dokploy infrastructure.

apps/mobile/src/__tests__/lib/profileSettingsApi.test.ts

@@ -0,0 +1,30 @@
+import { apiClient } from '../../lib/apiClient';
+import { profileSettingsApi } from '../../lib/profileSettingsApi';
+
+jest.mock('../../lib/apiClient', () => ({
+    apiClient: {
+        get: jest.fn(),
+        post: jest.fn(),
+        patch: jest.fn(),
+    },
+}));
+
+describe('profileSettingsApi', () => {
+    it('routes profile, activity, preference, and feedback operations through the standalone API', async () => {
+        await profileSettingsApi.updateProfile({ name: 'Alice' });
+        await profileSettingsApi.updateLastActive();
+        await profileSettingsApi.getNotificationPreferences();
+        await profileSettingsApi.updateNotificationPreference('messages_enabled', false);
+        await profileSettingsApi.submitFeedback({ type: 'bug', title: 'Title', description: 'Details' });
+
+        expect(apiClient.patch).toHaveBeenNthCalledWith(1, '/v1/me/profile', { name: 'Alice' });
+        expect(apiClient.post).toHaveBeenNthCalledWith(1, '/v1/me/activity');
+        expect(apiClient.get).toHaveBeenCalledWith('/v1/me/notification-preferences');
+        expect(apiClient.patch).toHaveBeenNthCalledWith(2, '/v1/me/notification-preferences', {
+            key: 'messages_enabled', value: false,
+        });
+        expect(apiClient.post).toHaveBeenNthCalledWith(2, '/v1/feedback', {
+            type: 'bug', title: 'Title', description: 'Details',
+        });
+    });
+});