chore: the poster-picker comments name their task #4491

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

backend/app/api/extension.py

@@ -123,7 +123,7 @@ async def quick_add_source():
     # Patreon is canon: adding a Patreon source to an existing artist can take
     # the creator's Patreon display name (name only; the slug never moves).
     use_platform_name = body.get("use_platform_name") is True
-    # #4488: a Discord add can carry the posters picked in the panel.
+    # #4491: a Discord add can carry the posters picked in the panel.
     discord_authors = body.get("discord_authors")
     if discord_authors is not None and not _valid_authors(discord_authors):
         return _bad("invalid_body", detail="discord_authors must be a list of {id, name}")
@@ -167,7 +167,7 @@ def _valid_authors(value) -> bool:
 @extension_bp.route("/discord/posters", methods=["GET"])
 async def discord_posters():
     """Who posts in the Discord channel `url` shows, lately, with the likely
-    creator marked (#4488). Reads the channel with the stored token; writes
+    creator marked (#4491). Reads the channel with the stored token; writes
     nothing."""
     url = (request.args.get("url") or "").strip()
     if not url: