fix: bound mark_seen's UID STORE with the configured timeout

aioimaplib forwards a timeout into IMAP4.uid(...) but drops it specifically for
the STORE command (protocol.uid() calls self.store(*criteria, by_uid=True)
without passing timeout through, so the Command never arms its internal timer).
Combined with IMAP4_SSL's default conn_lost_cb=None, a connection that goes
silent during a use_uid=True mark_seen call can hang the coroutine forever,
unlike the non-uid store path which is already wrapped by aioimaplib itself.
Wrap the uid-store call in asyncio.wait_for(self.timeout) so a stalled server
times out and mark_seen returns False like the rest of this method's contract.

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

src/aiomail/client.py

@@ -245,12 +245,18 @@ class IMAPClient:
         return None
 
     async def mark_seen(self, email_id: int) -> bool:
-        """flag a message as read without deleting it"""
+        """flag a message as read without deleting it
+
+        aioimaplib does not apply its own timeout to the UID STORE command path, so the
+        use_uid=True call is wrapped here to bound it the same as the non-uid path.
+        """
         if not await self.ensure_connection():
             return False
         try:
             if self.use_uid:
-                result, _ = await self._mail.uid("store", str(email_id), "+FLAGS", "(\\Seen)")
+                result, _ = await asyncio.wait_for(
+                    self._mail.uid("store", str(email_id), "+FLAGS", "(\\Seen)"), self.timeout
+                )
             else:
                 result, _ = await self._mail.store(str(email_id), "+FLAGS", "(\\Seen)")
             return result == "OK"