fix: reject a non-str stored token as stale before rebuilding the webhook (dpywebhooks-3)

Webhook.partial does no token validation of its own, so a store record with
token=None (e.g. a mongo/file store deserializing a missing field as null)
rebuilt and cached a token-less webhook with no error. Webhook.send then
raised a raw ValueError, not HTTPException, so send()'s dead-webhook except
never fired and the poisoned record was never cleared - the channel got
permanently stuck. Validate the token type before partial() so a bad record
takes the same clear-and-fall-through path as any other stale record.

Signed-off-by: disqualifier <dev@disqualifier.me>

src/dpy_webhooks/dpy_webhooks.py

@@ -351,11 +351,18 @@ class DPYWebhooks:
 
     async def _restore_from_store(self, channel: discord.TextChannel) -> "Optional[discord.Webhook]":
         """rebuild a partial webhook from the stored record; on a rebuild fault, treat the
-        record as stale (clear + return None so the caller can recreate)"""
+        record as stale (clear + return None so the caller can recreate)
+
+        Webhook.partial does no token validation of its own and will happily cache a
+        token-less webhook, which then raises a raw ValueError (not HTTPException) on
+        send - bypassing the self-heal path entirely and getting stuck forever. reject a
+        non-str token here, before partial(), so that record is treated as stale too"""
         record = await self._store.get(channel.id)
         if not record:
             return None
         try:
+            if not isinstance(record["token"], str):
+                raise TypeError(f"stored token must be str, got {type(record['token']).__name__}")
             webhook = discord.Webhook.partial(
                 int(record["webhook_id"]),
                 record["token"],