feat(integrations): add Google Health (Fit) integration with full permissions

OAuth2 flow with all 11 Google Fitness scopes (activity, body, sleep,
heart rate, nutrition, location, blood glucose/pressure/temperature,
oxygen saturation, reproductive health). Stores access + refresh tokens;
auto-refreshes on expiry.

GoogleHealthSignalSource fetches steps, sleep sessions, active minutes,
calories, and heart rate from the Fit aggregate + sessions APIs. Signals
flow into both the tip orchestrator and the health-vitals pre-compute
agent, which generates prompt snippets about step progress, sleep
deficit, sedentary time, and elevated heart rate.

Signal.kind extended with 'health'; IntegrationProvider extended with
'google-health'. Agent compute signal mapping enriched to include source,
kind, and all features so health-vitals can filter its own signals.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/api/src/routes/recommender.ts

@@ -10,6 +10,7 @@ import { bus } from '../events/bus.js';
 import type { TipCandidate, Signal } from '@oo/shared-types';
 import { todoistSource, dueAgeDays } from '../signals/todoist.js';
 export { dueAgeDays };
+import { googleHealthSource } from '../signals/google-health.js';
 import { SignalAggregator } from '../signals/aggregator.js';
 import { getActiveAgentOutputs } from './agent-outputs.js';
 import { getEligibleAgentIds } from '../profile/eligibility.js';
@@ -19,8 +20,11 @@ const router: ExpressRouter = Router();
 // ---------------------------------------------------------------------------
 // Signal aggregator — register sources here as new integrations are added
 // ---------------------------------------------------------------------------
-export const aggregator = new SignalAggregator().register(todoistSource);
-export const _clearSignalCacheForTests = () => todoistSource.clearCache();
+export const aggregator = new SignalAggregator().register(todoistSource).register(googleHealthSource);
+export const _clearSignalCacheForTests = () => {
+  todoistSource.clearCache();
+  googleHealthSource.clearCache();
+};
 
 // ---------------------------------------------------------------------------
 // Signal → TipCandidate conversion