feat: add prgs-reconciler profile and gated already-landed PR close (Closes #310)

Introduce a dedicated reconciler role with gitea_reconcile_already_landed_pr,
which closes open PRs only after live fetch and ancestor proof against a fresh
target branch. Document the gitea-reconciler namespace and extend task routing.

docs/gitea-execution-profiles.md

@@ -226,6 +226,24 @@ explicit operator-directed closure of a contaminated PR). If `close_pr` ever
 resolves as unknown, agents must fail closed rather than fall back to the
 edit path.
 
+## Reconciler profile for already-landed open PRs (#310)
+
+Normal author and reviewer profiles must not gain broad PR-close authority.
+Already-landed open PRs (head SHA is an ancestor of the target branch) need a
+dedicated reconciler profile such as `prgs-reconciler` with:
+
+- `gitea.read`
+- `gitea.pr.comment`
+- `gitea.issue.comment`
+- `gitea.issue.close`
+- `gitea.pr.close`
+
+Use the `gitea-reconciler` MCP namespace (static profile launch) and the
+`gitea_reconcile_already_landed_pr` tool. The resolver task is
+`reconcile_already_landed_pr`. PR close is allowed only after live PR fetch,
+fresh target-branch fetch, recorded target SHA, and ancestor proof. PRs whose
+heads are not already landed cannot be closed through this path.
+
 ## Identity and fail-closed rules
 
 Before **any** mutating action, a workflow must know both: