nisse-dev: a settled reply posted top-level is no point to answer either

nisse-review's review of #169: a reply quoting a top-level point, or one
Gitea refused on its line, arrives through list_comments, so answering it
would start the thank-you loop again. Also records what the live Gitea
showed: resolving is per comment, and resolving again is a 204.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

docs/Development-Plan.md

@@ -693,7 +693,8 @@ of earlier points, replies on threads, the round cap and its reset, `stop` and
   change). A settled reply carries `<!-- nisse-review: settled -->`. Being
   read-only (R3), the reviewer can't resolve the thread, so the PR's author
   does: nisse-dev resolves every comment on that thread's line when it next
-  watches the PR and takes the settled reply as no point to answer;
+  watches the PR and takes the settled reply as no point to answer (nor one
+  posted top-level, which has no thread to resolve);
   `scripts/resolve_settled.py` does the same for PRs made by hand.
 - **Sign-off:** `sign_off` posts a short review when there is nothing to raise;
   while it stays happy, a later review offers `still_happy`, which posts nothing