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/llm-workflow-runbooks.md

@@ -169,6 +169,25 @@ To avoid the bottleneck of relaunching/restarting the MCP server to switch betwe
   * `mcp__gitea-reviewer__*` (for reviewing PRs, approving, requesting changes, merging)
 * **Trust Model:** Separate tokens remain separate in the keychain/environment. Each instance operates under its own `GITEA_MCP_PROFILE` and enforces its own `allowed_operations`. A runtime `whoami` identity check is still performed independently, and self-review/self-merge checks remain strictly mandatory. The dual-server pattern is a operational convenience and never a security bypass.
 * **Reviewer-Identity PR Creation Deadlock:** Reviewer/merge identities must not create PRs or push branches. Doing so makes the reviewer identity the PR author in Gitea, blocking subsequent independent review and causing a review deadlock. Normally, PRs must be created by the author/work identity (`gitea-author`), leaving the reviewer identity (`gitea-reviewer`) clean and available for independent review and merge.
+* **Reconciler namespace (#310):** Register a third static instance for
+  already-landed PR cleanup when review queues block on open PRs whose heads
+  already landed on `master`:
+
+```json
+"gitea-reconciler": {
+  "command": "/path/to/Gitea-Tools/venv/bin/python3",
+  "args": ["/path/to/Gitea-Tools/mcp_server.py"],
+  "env": {
+    "GITEA_MCP_CONFIG": "/path/to/.config/gitea-tools/profiles.json",
+    "GITEA_MCP_PROFILE": "prgs-reconciler"
+  }
+}
+```
+
+  The reconciler profile grants `gitea.pr.close` only for
+  `gitea_reconcile_already_landed_pr` after ancestry proof — not for normal
+  review or author workflows.
+
 * **Fallback:** If the dual-profile MCP launcher pattern is not supported or configured in the client, the LLM must relaunch or restart the client/MCP with the correct profile environment variable before claiming or working on any tasks.
 
 ## Setup runbook — interactive menu