feat(author): harden reporting and claim capability per #183

- Add 'mark_issue' to TASK_MAP in resolve_task_capability for exact mutation proof (closes gap on unknown treated as allowed).
- Add assess_controller_handoff and integrate into build_final_report (downgrades missing handoff).
- Add tests for handoff and update existing.
- Update SKILL.md and review-pr.md to mandate exact 'Controller Handoff' section, exact sweep evidence, PR head SHA in reports.
- Author profile used throughout; no review/merge.

Refs #183

mcp_server.py

@@ -3337,6 +3337,10 @@ def gitea_resolve_task_capability(
             "permission": "gitea.issue.write",
             "role": "author",
         },
+        "mark_issue": {
+            "permission": "gitea.issue.write",
+            "role": "author",
+        },
         "create_branch": {
             "permission": "gitea.branch.create",
             "role": "author",