feat(pi): first-class support via pi-subagents + pi-ask-user (#651)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/skills/ce-work-beta/references/codex-delegation-workflow.md

@@ -66,7 +66,7 @@ If it shows an unresolved command string, run `command -v codex` using a shell t
 
 If `consent_granted` is not true (from config `work_delegate_consent`):
 
-Present a one-time consent warning using the platform's blocking question tool (AskUserQuestion in Claude Code). The consent warning explains:
+Present a one-time consent warning using the platform's blocking question tool (`AskUserQuestion` in Claude Code, `request_user_input` in Codex, `ask_user` in Gemini, `ask_user` in Pi (requires the `pi-ask-user` extension)). The consent warning explains:
 - Delegation sends implementation units to `codex exec` as a structured prompt
 - **yolo mode** (`--yolo`): Full system access including network. Required for verification steps that run tests or install dependencies. **Recommended.**
 - **full-auto mode** (`--full-auto`): Workspace-write sandbox, no network access.

plugins/compound-engineering/skills/ce-work-beta/references/shipping-workflow.md

@@ -32,7 +32,7 @@ This file contains the shipping workflow (Phase 3-4). Load it only when all Phas
 
    After Tier 2 code review completes, inspect the Residual Actionable Work summary it returned (or read the run artifact directly if the summary was not emitted). If one or more residual `downstream-resolver` findings remain, do not proceed to Final Validation until the user decides how to handle them.
 
-   Ask the user using the platform's blocking question tool (`AskUserQuestion` in Claude Code with `ToolSearch select:AskUserQuestion` pre-loaded if needed, `request_user_input` in Codex, `ask_user` in Gemini). Fall back to numbered options in chat only when the harness genuinely lacks a blocking tool. Never silently skip the gate.
+   Ask the user using the platform's blocking question tool (`AskUserQuestion` in Claude Code with `ToolSearch select:AskUserQuestion` pre-loaded if needed, `request_user_input` in Codex, `ask_user` in Gemini, `ask_user` in Pi (requires the `pi-ask-user` extension)). Fall back to numbered options in chat only when the harness genuinely lacks a blocking tool. Never silently skip the gate.
 
    Stem: `Code review found N residual finding(s) the skill did not auto-fix. How should the agent proceed?`
 

plugins/compound-engineering/skills/ce-work-beta/references/tracker-defer.md

@@ -144,6 +144,6 @@ When uncertain, prefer "drop with explicit user-facing notice" over "pass throug
 
 ## Cross-platform notes
 
-The question-tool name varies by platform. In Interactive mode, use the platform's blocking question tool (`AskUserQuestion` in Claude Code, `request_user_input` in Codex, `ask_user` in Gemini). In Claude Code the tool should already be loaded from the Interactive-mode pre-load step — if it isn't, call `ToolSearch` with query `select:AskUserQuestion` now. Fall back to numbered options in chat only when the harness genuinely lacks a blocking tool — `ToolSearch` returns no match, the tool call explicitly fails, or the runtime mode does not expose it (e.g., Codex edit modes without `request_user_input`). A pending schema load is not a fallback trigger. Never silently skip the question.
+The question-tool name varies by platform. In Interactive mode, use the platform's blocking question tool (`AskUserQuestion` in Claude Code, `request_user_input` in Codex, `ask_user` in Gemini, `ask_user` in Pi (requires the `pi-ask-user` extension)). In Claude Code the tool should already be loaded from the Interactive-mode pre-load step — if it isn't, call `ToolSearch` with query `select:AskUserQuestion` now. Fall back to numbered options in chat only when the harness genuinely lacks a blocking tool — `ToolSearch` returns no match, the tool call explicitly fails, or the runtime mode does not expose it (e.g., Codex edit modes without `request_user_input`). A pending schema load is not a fallback trigger. Never silently skip the question.
 
 Non-interactive mode is platform-agnostic: it never prompts, so the platform's question tool is not relevant.