Add orchestration loop phase and workflow execution skill

- Implemented Phase 2: Orchestration Loop for CCW Loop, including executor agent spawning, main loop execution, and iteration management.
- Introduced helper functions for action result parsing and user interaction.
- Created new skill: workflow-execute, coordinating agent execution for workflow tasks with automatic session discovery, parallel task processing, and status tracking.
- Defined execution flow, key design principles, and error handling strategies for the workflow execution process.

.codex/skills/ccw-loop/phases/01-session-init.md

@@ -0,0 +1,138 @@
+# Phase 1: Session Initialization
+
+Create or resume a development loop, initialize state file and directory structure.
+
+## Objective
+
+- Parse user arguments (TASK, --loop-id, --auto)
+- Create new loop with unique ID OR resume existing loop
+- Initialize directory structure for progress files
+- Create master state file
+- Output: loopId, state, progressDir
+
+## Execution
+
+### Step 1.1: Parse Arguments
+
+```javascript
+const { loopId: existingLoopId, task, mode = 'interactive' } = options
+
+// Validate mutual exclusivity
+if (!existingLoopId && !task) {
+  console.error('Either --loop-id or task description is required')
+  return { status: 'error', message: 'Missing loopId or task' }
+}
+
+// Determine mode
+const executionMode = options['--auto'] ? 'auto' : 'interactive'
+```
+
+### Step 1.2: Utility Functions
+
+```javascript
+const getUtc8ISOString = () => new Date(Date.now() + 8 * 60 * 60 * 1000).toISOString()
+
+function readLoopState(loopId) {
+  const stateFile = `.workflow/.loop/${loopId}.json`
+  if (!fs.existsSync(stateFile)) {
+    return null
+  }
+  return JSON.parse(Read(stateFile))
+}
+```
+
+### Step 1.3: New Loop Creation
+
+When `TASK` is provided (no `--loop-id`):
+
+```javascript
+// Generate unique loop ID
+const timestamp = getUtc8ISOString().replace(/[-:]/g, '').split('.')[0]
+const random = Math.random().toString(36).substring(2, 10)
+const loopId = `loop-v2-${timestamp}-${random}`
+
+console.log(`Creating new loop: ${loopId}`)
+```
+
+#### Create Directory Structure
+
+```bash
+mkdir -p .workflow/.loop/${loopId}.progress
+```
+
+#### Initialize State File
+
+```javascript
+function createLoopState(loopId, taskDescription) {
+  const stateFile = `.workflow/.loop/${loopId}.json`
+  const now = getUtc8ISOString()
+
+  const state = {
+    // API compatible fields
+    loop_id: loopId,
+    title: taskDescription.substring(0, 100),
+    description: taskDescription,
+    max_iterations: 10,
+    status: 'running',
+    current_iteration: 0,
+    created_at: now,
+    updated_at: now,
+
+    // Skill extension fields (initialized by INIT action)
+    skill_state: null
+  }
+
+  Write(stateFile, JSON.stringify(state, null, 2))
+  return state
+}
+```
+
+### Step 1.4: Resume Existing Loop
+
+When `--loop-id` is provided:
+
+```javascript
+const loopId = existingLoopId
+const state = readLoopState(loopId)
+
+if (!state) {
+  console.error(`Loop not found: ${loopId}`)
+  return { status: 'error', message: 'Loop not found' }
+}
+
+console.log(`Resuming loop: ${loopId}`)
+console.log(`Status: ${state.status}`)
+```
+
+### Step 1.5: Control Signal Check
+
+Before proceeding, verify loop status allows continuation:
+
+```javascript
+function checkControlSignals(loopId) {
+  const state = readLoopState(loopId)
+
+  switch (state?.status) {
+    case 'paused':
+      return { continue: false, action: 'pause_exit' }
+    case 'failed':
+      return { continue: false, action: 'stop_exit' }
+    case 'running':
+      return { continue: true, action: 'continue' }
+    default:
+      return { continue: false, action: 'stop_exit' }
+  }
+}
+```
+
+## Output
+
+- **Variable**: `loopId` - Unique loop identifier
+- **Variable**: `state` - Initialized or resumed loop state object
+- **Variable**: `progressDir` - `.workflow/.loop/${loopId}.progress`
+- **Variable**: `mode` - `'interactive'` or `'auto'`
+- **TodoWrite**: Mark Phase 1 completed, Phase 2 in_progress
+
+## Next Phase
+
+Return to orchestrator, then auto-continue to [Phase 2: Orchestration Loop](02-orchestration-loop.md).