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

backend/app/services/congress_api.py

@@ -126,6 +126,34 @@ def parse_bill_from_api(data: dict, congress: int) -> dict:
     }
 
 
+_STATE_NAME_TO_CODE: dict[str, str] = {
+    "Alabama": "AL", "Alaska": "AK", "Arizona": "AZ", "Arkansas": "AR",
+    "California": "CA", "Colorado": "CO", "Connecticut": "CT", "Delaware": "DE",
+    "Florida": "FL", "Georgia": "GA", "Hawaii": "HI", "Idaho": "ID",
+    "Illinois": "IL", "Indiana": "IN", "Iowa": "IA", "Kansas": "KS",
+    "Kentucky": "KY", "Louisiana": "LA", "Maine": "ME", "Maryland": "MD",
+    "Massachusetts": "MA", "Michigan": "MI", "Minnesota": "MN", "Mississippi": "MS",
+    "Missouri": "MO", "Montana": "MT", "Nebraska": "NE", "Nevada": "NV",
+    "New Hampshire": "NH", "New Jersey": "NJ", "New Mexico": "NM", "New York": "NY",
+    "North Carolina": "NC", "North Dakota": "ND", "Ohio": "OH", "Oklahoma": "OK",
+    "Oregon": "OR", "Pennsylvania": "PA", "Rhode Island": "RI", "South Carolina": "SC",
+    "South Dakota": "SD", "Tennessee": "TN", "Texas": "TX", "Utah": "UT",
+    "Vermont": "VT", "Virginia": "VA", "Washington": "WA", "West Virginia": "WV",
+    "Wisconsin": "WI", "Wyoming": "WY",
+    "American Samoa": "AS", "Guam": "GU", "Northern Mariana Islands": "MP",
+    "Puerto Rico": "PR", "Virgin Islands": "VI", "District of Columbia": "DC",
+}
+
+
+def _normalize_state(state: str | None) -> str | None:
+    if not state:
+        return None
+    s = state.strip()
+    if len(s) == 2:
+        return s.upper()
+    return _STATE_NAME_TO_CODE.get(s, s)
+
+
 def parse_member_from_api(data: dict) -> dict:
     """Normalize raw API member list data into our model fields."""
     terms = data.get("terms", {}).get("item", [])
@@ -136,9 +164,9 @@ def parse_member_from_api(data: dict) -> dict:
         "first_name": data.get("firstName"),
         "last_name": data.get("lastName"),
         "party": data.get("partyName") or None,
-        "state": data.get("state"),
+        "state": _normalize_state(data.get("state")),
         "chamber": current_term.get("chamber"),
-        "district": str(current_term.get("district")) if current_term.get("district") else None,
+        "district": str(data.get("district")) if data.get("district") else None,
         "photo_url": data.get("depiction", {}).get("imageUrl"),
         "official_url": data.get("officialWebsiteUrl"),
     }

backend/app/services/llm_service.py

@@ -418,6 +418,7 @@ def generate_draft_letter(
     selected_points: list[str],
     include_citations: bool,
     zip_code: str | None,
+    rep_name: str | None = None,
     llm_provider: str | None = None,
     llm_model: str | None = None,
 ) -> str:
@@ -436,12 +437,19 @@ def generate_draft_letter(
 
     location_line = f"The constituent is writing from ZIP code {zip_code}." if zip_code else ""
 
+    if rep_name:
+        title = "Senator" if recipient == "senate" else "Representative"
+        salutation_instruction = f'- Open with "Dear {title} {rep_name},"'
+    else:
+        salutation_instruction = f'- Open with "Dear {chamber_word} Member,"'
+
     prompt = f"""Write a short constituent letter to a {chamber_word} member of Congress.
 
 RULES:
 - {tone_instruction}
 - 6 to 12 sentences total.
-- First sentence must be a clear, direct ask: "Please vote {vote_word} on {bill_label}."
+- {salutation_instruction}
+- Second sentence must be a clear, direct ask: "Please vote {vote_word} on {bill_label}."
 - The body must reference ONLY the points listed below — do not invent any other claims or facts.
 - {citation_instruction}
 - Close with a brief sign-off and the placeholder "[Your Name]".