feat: roll-call votes + granular alert filter fix (v0.9.5)

Roll-call votes:
- Migration 0017: bill_votes + member_vote_positions tables
- Fetch vote XML directly from House Clerk / Senate LIS URLs
  embedded in bill actions recordedVotes objects
- GET /api/bills/{id}/votes triggers background fetch on first view
- VotePanel on bill detail: yea/nay bar, result badge, followed
  member positions with Sen./Rep. title, party badge, and state

Alert filter fix:
- _should_dispatch returns True when alert_filters is None so users
  who haven't saved filters still receive all notifications

Authored-By: Jack Levy

backend/app/workers/notification_dispatcher.py

@@ -66,7 +66,9 @@ def _should_dispatch(event, prefs: dict, follow_mode: str = "neutral") -> bool:
         if not key:
             key = "referral" if payload.get("milestone_tier") == "referral" else "vote"
 
-    all_filters = prefs.get("alert_filters") or {}
+    all_filters = prefs.get("alert_filters")
+    if all_filters is None:
+        return True  # user hasn't configured filters yet — send everything
     mode_filters = all_filters.get(follow_mode) or {}
     return bool(mode_filters.get(key, _FILTER_DEFAULTS.get(key, True)))