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

backend/app/workers/llm_processor.py

@@ -103,8 +103,16 @@ def process_document_with_llm(self, document_id: int):
 
         logger.info(f"{brief_type.capitalize()} brief {db_brief.id} created for bill {doc.bill_id} using {brief.llm_provider}/{brief.llm_model}")
 
-        # Emit notification events for users who follow this bill
-        _emit_notification_events(db, bill, doc.bill_id, brief_type, brief.summary)
+        # Emit notification events for bill followers, sponsor followers, and topic followers
+        from app.workers.notification_utils import (
+            emit_bill_notification,
+            emit_member_follow_notifications,
+            emit_topic_follow_notifications,
+        )
+        event_type = "new_amendment" if brief_type == "amendment" else "new_document"
+        emit_bill_notification(db, bill, event_type, brief.summary)
+        emit_member_follow_notifications(db, bill, event_type, brief.summary)
+        emit_topic_follow_notifications(db, bill, event_type, brief.summary, brief.topic_tags or [])
 
         # Trigger news fetch now that we have topic tags
         from app.workers.news_fetcher import fetch_news_for_bill
@@ -120,34 +128,6 @@ def process_document_with_llm(self, document_id: int):
         db.close()
 
 
-def _emit_notification_events(db, bill, bill_id: str, brief_type: str, summary: str | None) -> None:
-    """Create a NotificationEvent row for every user following this bill."""
-    from app.models.follow import Follow
-    from app.models.notification import NotificationEvent
-    from app.config import settings
-
-    followers = db.query(Follow).filter_by(follow_type="bill", follow_value=bill_id).all()
-    if not followers:
-        return
-
-    base_url = (settings.PUBLIC_URL or settings.LOCAL_URL).rstrip("/")
-    payload = {
-        "bill_title": bill.short_title or bill.title or "",
-        "bill_label": f"{bill.bill_type.upper()} {bill.bill_number}",
-        "brief_summary": (summary or "")[:300],
-        "bill_url": f"{base_url}/bills/{bill_id}",
-    }
-    event_type = "new_amendment" if brief_type == "amendment" else "new_document"
-
-    for follow in followers:
-        db.add(NotificationEvent(
-            user_id=follow.user_id,
-            bill_id=bill_id,
-            event_type=event_type,
-            payload=payload,
-        ))
-    db.commit()
-
 
 @celery_app.task(bind=True, name="app.workers.llm_processor.backfill_brief_citations")
 def backfill_brief_citations(self):