feat(cdt): add opt-in council review on plan before dev phase

[rube-de]

Part of #104

Context

CDT's auto-task Bridge (auto-task.md:70-72) goes directly from Phase 1 (planning) to Phase 2 (development) with just a log summary. The PM validates the plan, but PM is in the same team and shared context — it observed the design being built. An external AI review in fresh context catches assumptions and blind spots that in-context agents can't see.

The reviewer teammate already uses /council during code review — this extends the same pattern to plan review.

Task

Add an opt-in council review step to the auto-task Bridge. When enabled, run /council quick quality on the plan file before proceeding to Phase 2.

Acceptance Criteria

• VERIFY: Auto-task Bridge section includes a council review step
• VERIFY: Council review is opt-in — only runs when $ARGUMENTS includes --review-plan flag or plan metadata includes council_review: true
• VERIFY: When enabled, runs /council quick quality on the plan file path
• VERIFY: Council feedback is logged to the user before proceeding
• VERIFY: Council rejection does NOT block dev phase — it's advisory (logged as warning)
• VERIFY: When not enabled, Bridge proceeds as before (no latency added)

Implementation Guide

Files to Modify

• plugins/cdt/commands/auto-task.md — Add council review step to Bridge (after line 72)
• plugins/cdt/skills/cdt/references/plan-workflow.md — Add council_review to plan template metadata (optional)

Approach

1. In auto-task.md, Bridge section (after line 72 "proceed directly to development"), add:

   ### Optional: Council Review
   
   If `$ARGUMENTS` contains `--review-plan` OR the plan file metadata includes `council_review: true`:
   1. Run: Skill tool with skill "council", args "quick quality [plan-path]"
   2. Log council feedback to user
   3. If council raises critical concerns, log as WARNING but proceed (advisory only)
   4. Note: This adds latency (~30-60s). Skip for routine tasks.
   
   If neither flag is set, skip this step.
   

2. In plan-workflow.md, plan template metadata (near line 85), add:

   **Council Review**: [true|false] (default: false — enable for critical or high-risk features)
   

3. In plan-workflow.md, architect prompt, add a note:

   Set `Council Review: true` if the architecture involves security-critical code, complex state management, or novel patterns that benefit from external validation.
   

Patterns to Follow

• The reviewer teammate already invokes /council (dev-workflow.md:170) — same invocation pattern
• Auto-task's $ARGUMENTS parsing already handles flags (e.g., issue references at line 17 of plan-workflow.md)

Scope

In Scope

• Adding opt-in council review to auto-task Bridge
• Adding council_review metadata field to plan template
• Logging council feedback

Out of Scope

• Making council review mandatory
• Blocking dev phase on council rejection
• Adding council review to full-task or dev-task commands

Dependencies

• Blocked by: feat: add Doppler secrets management skill plugin #9 (acceptance criteria) — council reviews a more complete plan
• Blocks: None

Definition of Done

• Implementation complete
• bun scripts/validate-plugins.mjs passes
• PR approved and merged
• Epic checklist updated