bug: Copilot plan approval fails — integration worktree never created

[nigel-dev]

Description

When a plan is created in copilot mode, mc_plan saves the plan spec with status: 'pending' but does not create the integration branch or worktree. When the user later approves the plan via mc_plan_approve, it calls orchestrator.resumePlan(), which immediately accesses plan.integrationWorktree! — a field that was never populated.

This means copilot mode plans cannot be started after approval.

Steps to Reproduce

1. Create a plan in copilot mode:

   mc_plan(name: "test", mode: "copilot", jobs: [{name: "job1", prompt: "..."}])
   

2. Approve the plan:

   mc_plan_approve()
   

3. Observe failure when orchestrator tries to access plan.integrationWorktree.

Expected Behavior

After mc_plan_approve, the integration branch and worktree should be created (if they don't exist), and the plan should begin execution normally.

Actual Behavior

resumePlan() at src/lib/orchestrator.ts:846 accesses plan.integrationWorktree! which is undefined because copilot mode skips integration setup at src/tools/plan.ts:119-145.

Root Cause

In src/tools/plan.ts:

• Autopilot/supervisor (line 148+): Creates an Orchestrator and calls startPlan(spec), which internally creates the integration branch + worktree.
• Copilot (line 120-144): Only calls savePlan(spec) and returns — no integration setup.

Then in src/tools/plan-approve.ts:59:

• Calls orchestrator.resumePlan() which assumes integration infrastructure exists.

Proposed Fix

Either:

1. Have mc_plan_approve call orchestrator.startPlan(plan) instead of resumePlan() for pending plans (preferred — keeps plan creation lazy).
2. Have copilot mode in mc_plan create the integration branch/worktree before saving.

Files Involved

• src/tools/plan.ts:119-145 — copilot path skips integration setup
• src/tools/plan-approve.ts:52-59 — approval calls resumePlan() for pending plans
• src/lib/orchestrator.ts:846 — resumePlan() assumes integrationWorktree exists

Additional Context

Discovered during audit cross-reference (Feb 11, 2026). Related to issue #3 (supervisor checkpoint loop) — both stem from the plan approval path not properly bootstrapping the orchestrator state.