feat: Group-level execution mode control (Plan/Normal/Auto-accept mode switching)

[breaking-brake]

Summary

Add an execution mode property (plan / normal / auto-accept) to workflow group nodes, enabling automatic mode verification at group entry with user-guided mode switching when a mismatch is detected.

This feature applies only to Claude Code Export/Run — it does not affect other AI agent integrations (Copilot CLI, Codex CLI, etc.) or the MCP-based AI editing workflow.

Motivation

Different phases of a workflow require different levels of Claude Code's execution mode:

• Phase A (design/review): Plan mode — read-only planning, no file modifications
• Phase B (implementation): Auto-accept mode — execute changes without confirmation prompts

By associating an expected mode with each group, workflows can enforce the appropriate safety level per phase.

Investigation Results

Mode Control Feasibility

Mode	CLI/API Control	Prompt Control	Feasibility
Plan mode	EnterPlanMode tool is invoked by Claude itself; no external CLI flag	Can be prompted via instructions	○ Feasible
Normal mode	ExitPlanMode is registered in AVAILABLE_TOOLS	Default behavior	◎ Feasible
Auto-accept	CLI flag (--dangerously-skip-permissions) only at session startup; no dynamic toggle	Cannot be controlled via prompt	× Not programmable

Mode Detection

• Claude Code can self-report its current mode (Plan / Normal) at runtime
• There is no dedicated API/tool to return the mode, but prompting "check your current mode" reliably works
• Auto-accept mode status is not detectable from within the session

Key Constraint

Auto-accept cannot be toggled mid-session. The proposed UX handles this by prompting the user to switch modes manually and verifying the result, rather than attempting programmatic control.

Proposed UX Flow

Group entry
  ↓
Check current mode → Compare with expected mode
  ↓
  ├─ Match → Proceed with execution
  └─ Mismatch
       ↓
     Display: "Expected: Plan mode / Current: Normal mode"
              "Please press Shift+Tab to switch to Plan mode"
       ↓
     AskUserQuestion:
       1. I've switched — re-check
       2. Ignore and proceed as-is
       ↓
       ├─ 1 → Re-check mode (loop)
       └─ 2 → Continue with current mode

Implementation Plan

1. Schema Update (resources/workflow-schema.json)

Add mode property to group.fields:

"group": {
  "fields": {
    "label": { "type": "string", "required": true, "default": "Group" },
    "mode": {
      "type": "enum",
      "values": ["plan", "normal", "auto-accept", "none"],
      "required": false,
      "default": "none",
      "description": "Expected Claude Code execution mode for this group. Only used during Claude Code Export/Run."
    }
  }
}

2. Type Update (src/shared/types/workflow-definition.ts)

export interface GroupNodeData {
  label: string;
  mode?: 'plan' | 'normal' | 'auto-accept' | 'none';
}

3. Prompt Generation (src/extension/services/workflow-prompt-generator.ts)

Claude Code Export/Run only. When a group has a mode set, generate instructions at group entry to:

1. Self-check current mode
2. Compare with expected mode
3. If mismatch: display switching instructions and present re-check / skip options via AskUserQuestion

Other AI agent export formats (Copilot, Codex, etc.) will ignore the mode property.

4. UI (Webview)

Add a mode dropdown to the group node configuration panel.

Scope

• In scope: Plan / Normal / Auto-accept mode verification and user-guided switching during Claude Code Export/Run
• Out of scope:
  • Programmatic auto-accept toggling (technically impossible mid-session)
  • Mode control for non-Claude Code agents (Copilot CLI, Codex CLI, etc.)
  • MCP-based AI editing workflow