feat(notifications): follow modes, milestone alerts, notification enhancements

Follow Modes (neutral / pocket_veto / pocket_boost):
- Alembic migration 0013 adds follow_mode column to follows table
- FollowButton rewritten as mode-aware dropdown for bills; simple toggle for members/topics
- PATCH /api/follows/{id}/mode endpoint with validation
- Dispatcher filters pocket_veto follows (suppress new_document/new_amendment events)
- Dispatcher adds ntfy Actions header for pocket_boost follows

Change-driven (milestone) Alerts:
- New notification_utils.py with shared emit helpers and 30-min dedup
- congress_poller emits bill_updated events on milestone action text
- llm_processor replaced with shared emit util (also notifies member/topic followers)

Notification Enhancements:
- ntfy priority levels (high for bill_updated, default for others)
- Quiet hours (UTC): dispatcher holds events outside allowed window
- Digest mode (daily/weekly): send_notification_digest Celery beat task
- Notification history endpoint + Recent Alerts UI section
- Enriched following page (bill titles, member photos/details via sub-components)
- Follow mode test buttons in admin settings panel

Infrastructure:
- nginx: switch upstream blocks to set $variable proxy_pass so Docker DNS
  re-resolves upstream IPs after container rebuilds (valid=10s)
- TROUBLESHOOTING.md documenting common Docker/nginx/postgres gotchas

Authored-By: Jack Levy

frontend/lib/api.ts

@@ -9,6 +9,7 @@ import type {
   MemberTrendScore,
   MemberNewsArticle,
   NewsArticle,
+  NotificationEvent,
   NotificationSettings,
   PaginatedResponse,
   SettingsData,
@@ -98,6 +99,8 @@ export const followsAPI = {
     apiClient.post<Follow>("/api/follows", { follow_type, follow_value }).then((r) => r.data),
   remove: (id: number) =>
     apiClient.delete(`/api/follows/${id}`),
+  updateMode: (id: number, mode: string) =>
+    apiClient.patch<Follow>(`/api/follows/${id}/mode`, { follow_mode: mode }).then((r) => r.data),
 };
 
 // Dashboard
@@ -189,6 +192,10 @@ export const notificationsAPI = {
     apiClient.post<NotificationTestResult>("/api/notifications/test/ntfy", data).then((r) => r.data),
   testRss: () =>
     apiClient.post<NotificationTestResult>("/api/notifications/test/rss").then((r) => r.data),
+  testFollowMode: (mode: string, event_type: string) =>
+    apiClient.post<NotificationTestResult>("/api/notifications/test/follow-mode", { mode, event_type }).then((r) => r.data),
+  getHistory: () =>
+    apiClient.get<NotificationEvent[]>("/api/notifications/history").then((r) => r.data),
 };
 
 // Admin