fix(whatsapp_cloud): honor documented WHATSAPP_CLOUD_ALLOWED_USERS / ALLOW_ALL_USERS

The Cloud setup wizard and docs tell operators to set
WHATSAPP_CLOUD_ALLOWED_USERS (and WHATSAPP_CLOUD_ALLOW_ALL_USERS), but the
adapter DM intake gate only read WHATSAPP_CLOUD_ALLOW_FROM + WHATSAPP_CLOUD_DM_POLICY
(default open, opted-in only via GATEWAY_/WHATSAPP_ALLOW_ALL_USERS). So an
allowlist set via the documented var silently dropped every inbound
(_should_process_message -> None -> HTTP 200, no dispatch, no log line).

- _allow_from also reads WHATSAPP_CLOUD_ALLOWED_USERS
- dm_policy defaults to allowlist when an allowlist is present (else open)
- _open_dm_opted_in() also honors WHATSAPP_CLOUD_ALLOW_ALL_USERS

Explicit DM_POLICY / ALLOW_FROM still win -> backward compatible.

gateway/platforms/whatsapp_cloud.py

@@ -225,18 +225,35 @@ class WhatsAppCloudAdapter(WhatsAppBehaviorMixin, BasePlatformAdapter):
         import os
 
         self._reply_prefix: Optional[str] = extra.get("reply_prefix")
-        self._dm_policy: str = str(
-            extra.get("dm_policy")
-            or os.getenv("WHATSAPP_CLOUD_DM_POLICY")
-            or os.getenv("WHATSAPP_DM_POLICY", "open")
-        ).strip().lower()
+        # Allowlist: honor the *documented* WHATSAPP_CLOUD_ALLOWED_USERS (the
+        # var the setup wizard writes) in addition to WHATSAPP_CLOUD_ALLOW_FROM.
+        # The adapter historically read only ALLOW_FROM, so an allowlist
+        # configured via the documented var silently dropped every inbound.
         self._allow_from: set[str] = self._normalize_allow_ids(
             self._coerce_allow_list(
                 extra.get("allow_from")
                 or extra.get("allowFrom")
                 or os.getenv("WHATSAPP_CLOUD_ALLOW_FROM")
+                or os.getenv("WHATSAPP_CLOUD_ALLOWED_USERS")
             )
         )
+        # DM policy: explicit config wins; otherwise choose a safe, working
+        # default -- "open" if the operator opted into allow-all, else
+        # "allowlist" when an allowlist is configured (so it is actually
+        # enforced instead of silently dropping), else "open".
+        _allow_all_optin = str(
+            os.getenv("WHATSAPP_CLOUD_ALLOW_ALL_USERS", "")
+        ).strip().lower() in {"true", "1", "yes"}
+        _default_dm_policy = (
+            "open" if _allow_all_optin
+            else ("allowlist" if self._allow_from else "open")
+        )
+        self._dm_policy: str = str(
+            extra.get("dm_policy")
+            or os.getenv("WHATSAPP_CLOUD_DM_POLICY")
+            or os.getenv("WHATSAPP_DM_POLICY")
+            or _default_dm_policy
+        ).strip().lower()
         self._group_policy: str = str(
             extra.get("group_policy")
             or os.getenv("WHATSAPP_CLOUD_GROUP_POLICY")
@@ -347,6 +364,17 @@ class WhatsAppCloudAdapter(WhatsAppBehaviorMixin, BasePlatformAdapter):
             return (bare or sender_id) in self._allow_from
         return super()._is_dm_allowed(sender_id)
 
+    def _open_dm_opted_in(self) -> bool:
+        """Also honor the documented WHATSAPP_CLOUD_ALLOW_ALL_USERS opt-in.
+
+        The shared mixin only checks GATEWAY_ALLOW_ALL_USERS /
+        WHATSAPP_ALLOW_ALL_USERS; the Cloud adapter's documented open-access
+        opt-in is WHATSAPP_CLOUD_ALLOW_ALL_USERS, so honor it here too.
+        """
+        if str(os.getenv("WHATSAPP_CLOUD_ALLOW_ALL_USERS", "")).strip().lower() in {"true", "1", "yes"}:
+            return True
+        return super()._open_dm_opted_in()
+
     # ------------------------------------------------------------------ lifecycle
     async def connect(self, *, is_reconnect: bool = False) -> bool:
         if not check_whatsapp_cloud_requirements():