feat: add sort param to messages endpoint, default desc (newest first)

src/api/messages.py

@@ -17,8 +17,13 @@ async def list_messages(
     from_addr: Optional[str] = Query(default=None, alias="from"),
     limit: int = Query(default=50, le=200),
     offset: int = Query(default=0),
+    sort: str = Query(default="desc", regex="^(asc|desc)$"),
 ) -> list[Message]:
-    """List messages in a folder."""
+    """List messages in a folder.
+    
+    Args:
+        sort: Sort order by date. "desc" (default) = newest first, "asc" = oldest first
+    """
     config = get_config()
     
     if account_id not in config.accounts:
@@ -36,6 +41,10 @@ async def list_messages(
                 from_addr=from_addr,
             )
             
+            # Sort by UID (higher UID = newer message)
+            if sort == "desc":
+                uids = list(reversed(uids))
+            
             # Apply pagination
             total = len(uids)
             uids = uids[offset:offset + limit]