feat: Phase 3 complete — push alerts, feedback scoring, S3 fallback, SPA routing, mobile CSS

- ImpactScoreService: implement getFeedbackBonus() (ST_Distance query on UserFeedback within 20km/6h)
- ImpactScoreService: trigger PushNotificationService when score >= 70
- PushNotificationService: send VAPID WebPush to spot subscribers, clean expired subs
- PushController: GET vapid-public-key, POST/DELETE subscribe with rate limiting
- SentinelHubClient: add optional $collection param, add Sentinel-3 OLCI FAI evalscript (MCI)
- IngestionService: add $collection param + HighCloudCoverageException for fallback logic
- IngestionService: add ingestWithFallback() — tries S2, falls back to S3 on high cloud
- IngestSentinelCommand: --source=auto (default) triggers ingestWithFallback
- FeedbackController: rate limiting via apiFeedbackLimiter
- Migration: push_subscription table
- rate_limiter.yaml: api_read(120/min), api_feedback(10/min), api_push(5/min)
- sw.js: service worker handling push events + notificationclick
- usePushSubscription hook: subscribe/unsubscribe lifecycle with VAPID
- SpotPanel: PushButton component integrated
- SpotPanel.css + TimelineSlider.css: mobile responsive (bottom-sheet on small screens)
- Caddyfile: SPA served at / with try_files fallback, sw.js served from root scope
- vite.config.js: build outDir → backend/public (not /spa)
- deploy/post-receive.sh: full deploy script (composer, npm build, migrations, cache, docker up)
- docs/roadmap.md: all Phase 3 + transversal items marked done

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

frontend/src/api/client.js

@@ -40,4 +40,16 @@ export const api = {
   feedback: {
     create: (data) => post('/feedback', data),
   },
+  push: {
+    vapidKey:    ()     => get('/push/vapid-public-key'),
+    subscribe:   (data) => post('/push/subscribe', data),
+    unsubscribe: async (endpoint) => {
+      const res = await fetch(BASE_URL + '/push/subscribe', {
+        method: 'DELETE',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ endpoint }),
+      });
+      if (!res.ok && res.status !== 204) throw new Error(`API error ${res.status}`);
+    },
+  },
 };