feat: ZIP → rep lookup, member page redesign, letter improvements

ZIP lookup (GET /api/members/by-zip/{zip}):
- Two-step geocoding: Nominatim (ZIP → lat/lng) then Census TIGERweb
  Legislative identify (lat/lng → congressional district via GEOID)
- Handles at-large states (AK, DE, MT, ND, SD, VT, WY)
- Added rep_lookup health check to admin External API Health panel

congress_api.py fixes:
- parse_member_from_api: normalize state full name → 2-letter code
  (Congress.gov returns "Florida", DB expects "FL")
- parse_member_from_api: read district from top-level data field,
  not current_term (district is not inside the term object)

Celery beat: schedule sync_members daily at 1 AM UTC so chamber,
district, and contact info stay current without manual triggering

Members page redesign: photo avatars, party/state/chamber chips,
phone + website links, ZIP lookup form to find your reps

Draft letter improvements: pass rep_name from ZIP lookup so letter
opens with "Dear Representative Franklin," instead of generic salutation;
add has_document filter to bills list endpoint

UX additions: HelpTip component, How It Works page, "How it works"
sidebar nav link, collections page description copy

Authored-By: Jack Levy

frontend/app/bills/page.tsx

@@ -1,8 +1,8 @@
 "use client";
 
-import { useState } from "react";
+import { useState, useEffect } from "react";
 import { useSearchParams } from "next/navigation";
-import { Search } from "lucide-react";
+import { FileText, Search } from "lucide-react";
 import { useBills } from "@/lib/hooks/useBills";
 import { BillCard } from "@/components/shared/BillCard";
 
@@ -19,12 +19,22 @@ export default function BillsPage() {
   const [q, setQ] = useState(searchParams.get("q") ?? "");
   const [chamber, setChamber] = useState(searchParams.get("chamber") ?? "");
   const [topic, setTopic] = useState(searchParams.get("topic") ?? "");
+  const [hasText, setHasText] = useState(false);
   const [page, setPage] = useState(1);
 
+  // Sync URL params → state so tag/topic links work when already on this page
+  useEffect(() => {
+    setQ(searchParams.get("q") ?? "");
+    setChamber(searchParams.get("chamber") ?? "");
+    setTopic(searchParams.get("topic") ?? "");
+    setPage(1);
+  }, [searchParams]);
+
   const params = {
     ...(q && { q }),
     ...(chamber && { chamber }),
     ...(topic && { topic }),
+    ...(hasText && { has_document: true }),
     page,
     per_page: 20,
     sort: "latest_action_date",
@@ -67,6 +77,18 @@ export default function BillsPage() {
           <option value="">All Topics</option>
           {TOPICS.slice(1).map((t) => <option key={t} value={t}>{t}</option>)}
         </select>
+        <button
+          onClick={() => { setHasText((v) => !v); setPage(1); }}
+          className={`flex items-center gap-1.5 px-3 py-2 text-sm rounded-md border transition-colors ${
+            hasText
+              ? "bg-primary text-primary-foreground border-primary"
+              : "bg-card border-border text-muted-foreground hover:bg-accent hover:text-foreground"
+          }`}
+          title="Show only bills with published text"
+        >
+          <FileText className="w-3.5 h-3.5" />
+          Has text
+        </button>
       </div>
 
       {/* Results */}