Require a complete PCM return address before placing orders.

Empty PCM_RETURN_ADDRESS was sending SITE_NAME as firstName with blank street fields, which PCM rejects with 400; validate early and wire PCM env through compose.

site/messaging/providers/postcard/pcm.py

@@ -193,38 +193,82 @@ def pcm_request(
 
 
 def return_address_from_settings() -> dict[str, str]:
-    """Build PCM returnAddress from PCM_RETURN_ADDRESS JSON or CONTACT_* vars."""
+    """Build PCM returnAddress from PCM_RETURN_ADDRESS JSON and/or PCM_RETURN_* vars.
+
+    PCM requires address/city/state (and zip) whenever firstName is set — an empty
+    street with SITE_NAME-derived firstName causes a 400 from POST /order/postcard.
+    """
+    data: dict[str, Any] = {}
     raw = (settings.PCM_RETURN_ADDRESS or "").strip()
     if raw:
-        data = json.loads(raw)
-        if not isinstance(data, dict):
+        try:
+            parsed = json.loads(raw)
+        except json.JSONDecodeError as exc:
+            raise PcmApiError(
+                "PCM_RETURN_ADDRESS must be valid JSON "
+                '(e.g. {"firstName":"…","lastName":"…","address":"…",'
+                '"city":"…","state":"IL","zipCode":"…"})'
+            ) from exc
+        if not isinstance(parsed, dict):
             raise PcmApiError("PCM_RETURN_ADDRESS must be a JSON object")
-        return {
-            "company": str(data.get("company") or ""),
-            "firstName": str(data.get("firstName") or data.get("first_name") or ""),
-            "lastName": str(data.get("lastName") or data.get("last_name") or ""),
-            "address": str(data.get("address") or data.get("line1") or ""),
-            "address2": str(data.get("address2") or data.get("line2") or ""),
-            "city": str(data.get("city") or ""),
-            "state": str(data.get("state") or ""),
-            "zipCode": str(data.get("zipCode") or data.get("zip") or ""),
-        }
+        data = parsed
 
     name = (settings.SITE_NAME or "").strip()
     parts = name.split(None, 1)
-    first = parts[0] if parts else "Monica"
-    last = parts[1] if len(parts) > 1 else ""
-    return {
-        "company": "",
-        "firstName": first,
-        "lastName": last,
-        "address": str(getattr(settings, "PCM_RETURN_LINE1", "") or ""),
-        "address2": str(getattr(settings, "PCM_RETURN_LINE2", "") or ""),
-        "city": str(getattr(settings, "PCM_RETURN_CITY", "") or ""),
-        "state": str(getattr(settings, "PCM_RETURN_STATE", "") or ""),
-        "zipCode": str(getattr(settings, "PCM_RETURN_ZIP", "") or ""),
+    site_first = parts[0] if parts else ""
+    site_last = parts[1] if len(parts) > 1 else ""
+
+    address = {
+        "company": str(data.get("company") or "").strip(),
+        "firstName": str(
+            data.get("firstName") or data.get("first_name") or site_first or ""
+        ).strip(),
+        "lastName": str(
+            data.get("lastName") or data.get("last_name") or site_last or ""
+        ).strip(),
+        "address": str(
+            data.get("address")
+            or data.get("line1")
+            or getattr(settings, "PCM_RETURN_LINE1", "")
+            or ""
+        ).strip(),
+        # PCM treats blank address2 oddly; space matches recipient payload.
+        "address2": str(
+            data.get("address2")
+            or data.get("line2")
+            or getattr(settings, "PCM_RETURN_LINE2", "")
+            or ""
+        ).strip()
+        or " ",
+        "city": str(
+            data.get("city") or getattr(settings, "PCM_RETURN_CITY", "") or ""
+        ).strip(),
+        "state": str(
+            data.get("state") or getattr(settings, "PCM_RETURN_STATE", "") or ""
+        ).strip(),
+        "zipCode": str(
+            data.get("zipCode")
+            or data.get("zip")
+            or getattr(settings, "PCM_RETURN_ZIP", "")
+            or ""
+        ).strip(),
     }
 
+    missing = [
+        field
+        for field in ("firstName", "address", "city", "state", "zipCode")
+        if not address.get(field, "").strip()
+    ]
+    if missing:
+        raise PcmApiError(
+            "PCM return address incomplete (missing "
+            + ", ".join(missing)
+            + "). Set PCM_RETURN_ADDRESS JSON with firstName, lastName, "
+            "address, city, state, zipCode "
+            "(or PCM_RETURN_LINE1 / CITY / STATE / ZIP)."
+        )
+    return address
+
 
 def contact_to_pcm_recipient(contact, *, ext_ref: str) -> dict[str, str]:
     address = contact.postal_address or {}