Add bill action pipeline, admin health panel, and LLM provider fixes

- Fetch bill actions from Congress.gov and populate the action timeline
- Add nightly batch task and beat schedule for active bill actions
- Add admin reprocess endpoint for per-bill debugging
- Add BriefPanel with "What Changed" view and version history
- Add External API Health section with per-source latency testing
- Redesign Manual Controls as health panel with status dots and descriptions
- Add Resume Analysis task for stalled LLM jobs
- Add Backfill Dates & Links task for bills with null metadata
- Fix LLM provider/model DB overrides being ignored (env vars used instead)
- Fix Gemini 404: gemini-1.5-pro deprecated → gemini-2.0-flash
- Fix Anthropic models list: use REST API directly (SDK too old for .models)
- Replace test-LLM full analysis with lightweight ping (max_tokens=20)
- Add has_document field to BillDetail; show "No bill text published" state
- Fix "Introduced: —" showing for bills with null introduced_date
- Add bills_missing_sponsor and bills_missing_metadata to admin stats
- Add GovInfo health check using /collections endpoint (fixes 500 from /packages)

Authored-By: Jack Levy

backend/app/workers/congress_poller.py

@@ -300,17 +300,95 @@ def fetch_actions_for_active_bills(self):
 def _update_bill_if_changed(db, existing: Bill, parsed: dict) -> bool:
     """Update bill fields if anything has changed. Returns True if updated."""
     changed = False
+    dirty = False
+
+    # Meaningful change fields — trigger document + action fetch when updated
     track_fields = ["title", "short_title", "latest_action_date", "latest_action_text", "status"]
     for field in track_fields:
         new_val = parsed.get(field)
         if new_val and getattr(existing, field) != new_val:
             setattr(existing, field, new_val)
             changed = True
+            dirty = True
+
+    # Static fields — only fill in if currently null; no change trigger needed
+    fill_null_fields = ["introduced_date", "congress_url", "chamber"]
+    for field in fill_null_fields:
+        new_val = parsed.get(field)
+        if new_val and getattr(existing, field) is None:
+            setattr(existing, field, new_val)
+            dirty = True
+
     if changed:
         existing.last_checked_at = datetime.now(timezone.utc)
+    if dirty:
         db.commit()
-        # Check for new text versions and sync actions now that the bill has changed
+    if changed:
         from app.workers.document_fetcher import fetch_bill_documents
         fetch_bill_documents.delay(existing.bill_id)
         fetch_bill_actions.delay(existing.bill_id)
     return changed
+
+
+@celery_app.task(bind=True, name="app.workers.congress_poller.backfill_bill_metadata")
+def backfill_bill_metadata(self):
+    """
+    Find bills with null introduced_date (or other static fields) and
+    re-fetch their detail from Congress.gov to fill in the missing values.
+    No document or LLM calls — metadata only.
+    """
+    db = get_sync_db()
+    try:
+        from sqlalchemy import text as sa_text
+        rows = db.execute(sa_text("""
+            SELECT bill_id, congress_number, bill_type, bill_number
+            FROM bills
+            WHERE introduced_date IS NULL
+               OR congress_url IS NULL
+               OR chamber IS NULL
+        """)).fetchall()
+
+        updated = 0
+        skipped = 0
+        for row in rows:
+            try:
+                detail = congress_api.get_bill_detail(
+                    row.congress_number, row.bill_type, row.bill_number
+                )
+                bill_data = detail.get("bill", {})
+                parsed = congress_api.parse_bill_from_api(
+                    {
+                        "type": row.bill_type,
+                        "number": row.bill_number,
+                        "introducedDate": bill_data.get("introducedDate"),
+                        "title": bill_data.get("title"),
+                        "shortTitle": bill_data.get("shortTitle"),
+                        "latestAction": bill_data.get("latestAction") or {},
+                    },
+                    row.congress_number,
+                )
+                bill = db.get(Bill, row.bill_id)
+                if not bill:
+                    skipped += 1
+                    continue
+                fill_null_fields = ["introduced_date", "congress_url", "chamber", "title", "short_title"]
+                dirty = False
+                for field in fill_null_fields:
+                    new_val = parsed.get(field)
+                    if new_val and getattr(bill, field) is None:
+                        setattr(bill, field, new_val)
+                        dirty = True
+                if dirty:
+                    db.commit()
+                    updated += 1
+                else:
+                    skipped += 1
+                time.sleep(0.2)  # ~300 req/min — well under the 5k/hr limit
+            except Exception as exc:
+                logger.warning(f"backfill_bill_metadata: failed for {row.bill_id}: {exc}")
+                skipped += 1
+
+        logger.info(f"backfill_bill_metadata: {updated} updated, {skipped} skipped")
+        return {"updated": updated, "skipped": skipped}
+    finally:
+        db.close()