feat: add reply/forward/pin message flow across backend and web

- add reply_to/forwarded_from message fields and chat pinned_message field

- add forward and pin APIs plus reply support in message create

- wire web actions: Reply, Fwd, Pin and reply composer state

- fix spam policy bug: allow repeated identical messages, keep rate limiting

app/messages/repository.py

@@ -10,10 +10,19 @@ async def create_message(
     *,
     chat_id: int,
     sender_id: int,
+    reply_to_message_id: int | None,
+    forwarded_from_message_id: int | None,
     message_type: MessageType,
     text: str | None,
 ) -> Message:
-    message = Message(chat_id=chat_id, sender_id=sender_id, type=message_type, text=text)
+    message = Message(
+        chat_id=chat_id,
+        sender_id=sender_id,
+        reply_to_message_id=reply_to_message_id,
+        forwarded_from_message_id=forwarded_from_message_id,
+        type=message_type,
+        text=text,
+    )
     db.add(message)
     await db.flush()
     return message