Add Patch operation to Site entity (was only Put, causing 405 errors).
Fix migration to use ALTER TABLE DROP CONSTRAINT instead of DROP INDEX
for the piece name unique constraint.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Create Comment entity with API Platform annotations (GET, PATCH, DELETE).
Add CommentController with POST (create), PATCH (resolve) and GET
(unresolved count) endpoints. Add migration for comments table and
piece reference unique index.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>