feat(threads): add basic message thread API and web thread panel

app/messages/repository.py

@@ -124,6 +124,34 @@ async def search_messages(
     return list(result.scalars().all())
 
 
+async def list_message_thread(
+    db: AsyncSession,
+    *,
+    root_message_id: int,
+    user_id: int,
+    limit: int = 100,
+) -> list[Message]:
+    root = await get_message_by_id(db, root_message_id)
+    if not root:
+        return []
+    stmt = (
+        select(Message)
+        .outerjoin(
+            MessageHidden,
+            (MessageHidden.message_id == Message.id) & (MessageHidden.user_id == user_id),
+        )
+        .where(
+            Message.chat_id == root.chat_id,
+            MessageHidden.id.is_(None),
+            (Message.id == root_message_id) | (Message.reply_to_message_id == root_message_id),
+        )
+        .order_by(Message.id.asc())
+        .limit(max(1, min(limit, 200)))
+    )
+    result = await db.execute(stmt)
+    return list(result.scalars().all())
+
+
 async def delete_message(db: AsyncSession, message: Message) -> None:
     await db.delete(message)