feat: add pi reviewer support to workflow variants

docs/CREATE-PLAN.md

@@ -33,6 +33,7 @@ To use the iterative plan review feature, one of these CLIs must be installed:
 | `codex` | `npm install -g @openai/codex` | `codex --version` |
 | `claude` | `npm install -g @anthropic-ai/claude-code` | `claude --version` |
 | `cursor` | `curl https://cursor.com/install -fsS \| bash` | `cursor-agent --version` (binary: `cursor-agent`; alias `cursor agent` also works) |
+| `pi` | Install Pi coding agent | `pi --version`; list models with `pi --list-models [search]` |
 
 The reviewer CLI is independent of which agent is running the planning — e.g., Claude Code can send plans to Codex for review, and vice versa.
 
@@ -188,6 +189,7 @@ ts=<ISO-8601> level=<info|warn|error> state=<running-silent|running-active|in-pr
 | `codex` | `codex exec -m <model> -s read-only` | Yes (`codex exec resume <id>`) | `-s read-only` |
 | `claude` | `claude -p --model <model> --strict-mcp-config --setting-sources user` | No (fresh call each round) | `--strict-mcp-config --setting-sources user` |
 | `cursor` | `cursor-agent -p --mode=ask --model <model> --trust --output-format json` | Yes (`--resume <id>`) | `--mode=ask` |
+| `pi` | See [PI-COMMON-REVIEWER.md](./PI-COMMON-REVIEWER.md) | No (fresh call each round) | `--tools read,grep,find,ls` |
 
 For all three CLIs, the preferred execution path is:
 
@@ -195,6 +197,16 @@ For all three CLIs, the preferred execution path is:
 2. run that script through `reviewer-runtime/run-review.sh`
 3. fall back to direct synchronous execution only if the helper is missing or not executable
 
+
+
+## Pi Reviewer Support
+
+All workflow variants can use Pi itself as a reviewer CLI. Use `pi/<pi-model-name>` shorthand, for example `pi/claude-opus-4-7`; this means `REVIEWER_CLI=pi` and `REVIEWER_MODEL=claude-opus-4-7`. Provider-qualified or multi-slash Pi model IDs are preserved after the first `pi/` prefix, for example `pi/anthropic/claude-opus-4-7`.
+
+The canonical isolated read-only Pi reviewer flag contract lives in [PI-COMMON-REVIEWER.md](./PI-COMMON-REVIEWER.md). This workflow passes the plan review payload at `/tmp/plan-${REVIEW_ID}.md` and expects the standard `## Summary`, `## Findings`, and `## Verdict` response. Pi reviewer output is captured as markdown stdout, not JSON.
+
+If the Pi reviewer model or provider is unavailable, surface the helper stderr/status and use `pi --list-models [search]` to inspect configured models.
+
 ## Notifications
 
 - Telegram is the only supported notification path.