fix: support AI commands in media captions

app/commands/dispatcher.py

@@ -59,10 +59,12 @@ class CommandDispatcher:
         account: "AccountState",
     ) -> bool:
         text = getattr(message, "text", None)
-        if not isinstance(text, str):
+        caption = getattr(message, "caption", None)
+        command_text = text if isinstance(text, str) else caption
+        if not isinstance(command_text, str):
             return False
 
-        parsed = parse_command(text)
+        parsed = parse_command(command_text)
         if parsed is None:
             return False
 
@@ -85,7 +87,7 @@ class CommandDispatcher:
             message=message,
             command=definition,
             prefix=parsed.prefix,
-            raw_text=text,
+            raw_text=command_text,
             args=parsed.args,
             alias=parsed.alias,
         )