Add EDDM size, income, businesses and USPS map link (#17)

## Summary
Closes #17.
- Join USPS EDDM GIS stats onto the carrier-route picker (household size, median income, business count) and link to the official EDDM map.
- GIS miss stays a dash and does not block Find routes; PCM households/cost unchanged.

site/messaging/services.py

@@ -456,6 +456,10 @@ def postcard_quote(*, action: str, payload: dict) -> dict:
         mail_class_for_size,
         pick_unit_price,
     )
+    from messaging.providers.postcard.usps_eddm import (
+        USPS_EDDM_MAP_URL,
+        enrich_crrt_rows,
+    )
 
     template_id = str(payload.get("template_id") or "").strip()
     design_id = payload.get("design_id")
@@ -511,7 +515,7 @@ def postcard_quote(*, action: str, payload: dict) -> dict:
             data = list_count_zipcode(zip_codes=[zip_code])
         else:
             raise ValueError("Enter a ZIP code (or address + ZIP + radius).")
-        rows = extract_crrt_rows(data)
+        rows = enrich_crrt_rows(extract_crrt_rows(data), zip_hint=zip_code)
         priced = []
         for row in rows:
             per_piece, source = _price(row["total"])
@@ -528,6 +532,7 @@ def postcard_quote(*, action: str, payload: dict) -> dict:
             "mail_class": mail_class,
             "zip": zip_code,
             "routes": priced,
+            "eddm_map_url": USPS_EDDM_MAP_URL,
             "discovery_list_count_id": data.get("listCountID") or data.get("list_count_id"),
         }
 
@@ -553,6 +558,7 @@ def postcard_quote(*, action: str, payload: dict) -> dict:
             rows = [{"code": code, "text": code, "total": 0} for code in codes]
             if record_count and len(rows) == 1:
                 rows[0]["total"] = record_count
+        rows = enrich_crrt_rows(rows, zip_hint=codes[0] if codes else "")
         record_count = int(data.get("recordCount") or data.get("record_count") or 0)
         if not record_count:
             record_count = sum(int(r.get("total") or 0) for r in rows)
@@ -580,6 +586,7 @@ def postcard_quote(*, action: str, payload: dict) -> dict:
             "per_piece": per_piece,
             "total": money_total(per_piece, record_count),
             "price_source": source,
+            "eddm_map_url": USPS_EDDM_MAP_URL,
             "estimated": {
                 "per_piece": per_piece,
                 "pieces": record_count,