fix(workflow): complete path migration and enhance session:complete

Comprehensive update to eliminate all old path references and implement transactional archival in session:complete.

## Part 1: Complete Path Migration (43 files)

### Files Updated
- action-plan-verify.md
- session/list.md, session/resume.md
- tdd-verify.md, tdd-plan.md, test-*.md
- All brainstorm/*.md files (13 files)
- All tools/*.md files (10 files)
- All ui-design/*.md files (10 files)
- lite-plan.md, lite-execute.md, plan.md

### Path Changes
- `.workflow/.active-*` → `find .workflow/sessions/ -name "WFS-*" -type d`
- `.workflow/WFS-{session}` → `.workflow/sessions/WFS-{session}`
- `.workflow/.archives/` → `.workflow/archives/`
- Removed all marker file operations (touch/rm .active-*)

### Verification
- ✅ 0 references to .active-* markers remain
- ✅ 0 references to direct .workflow/WFS-* paths
- ✅ 0 references to .workflow/.archives/ (dot prefix)

## Part 2: Transactional Archival Enhancement

### session/complete.md - Complete Rewrite

**New Four-Phase Architecture**:

1. **Phase 1: Pre-Archival Preparation**
   - Find active session in .workflow/sessions/
   - Check for existing .archiving marker (resume detection)
   - Create .archiving marker to prevent concurrent operations

2. **Phase 2: Agent Analysis (In-Place)**
   - Agent processes session WHILE STILL in sessions/ directory
   - Pure analysis - no file moves or manifest updates
   - Returns complete metadata package for atomic commit
   - Failure here → session remains active, safe to retry

3. **Phase 3: Atomic Commit**
   - Only executes if Phase 2 succeeds
   - Move session to archives/
   - Update manifest.json
   - Remove .archiving marker
   - All-or-nothing guarantee

4. **Phase 4: Project Registry Update**
   - Extract feature metadata and update project.json

**Key Improvements**:
- **Agent-first, move-second**: Prevents inconsistent states
- **Transactional guarantees**: All-or-nothing file operations
- **Resume capability**: .archiving marker enables safe retry
- **Error recovery**: Comprehensive failure handling documented

**Old Design Flaw (Fixed)**:
- Old: Move first → Agent processes → If agent fails, session moved but metadata incomplete
- New: Agent processes → If success, atomic commit → Guaranteed consistency

## Benefits

1. **Consistency**: All commands use identical path patterns
2. **Robustness**: Transactional archival prevents data loss
3. **Maintainability**: Single source of truth for directory structure
4. **Recoverability**: Failed operations can be safely retried
5. **Alignment**: Closer to OpenSpec's clean three-layer model

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.claude/commands/workflow/tools/test-task-generate.md

@@ -273,19 +273,19 @@ const agentContext = {
   // Use memory if available, else load
   session_metadata: memory.has("workflow-session.json")
     ? memory.get("workflow-session.json")
-    : Read(.workflow/WFS-test-[id]/workflow-session.json),
+    : Read(.workflow/sessions/WFS-test-[id]/workflow-session.json),
 
-  test_analysis_results_path: ".workflow/WFS-test-[id]/.process/TEST_ANALYSIS_RESULTS.md",
+  test_analysis_results_path: ".workflow/sessions/WFS-test-[id]/.process/TEST_ANALYSIS_RESULTS.md",
 
   test_analysis_results: memory.has("TEST_ANALYSIS_RESULTS.md")
     ? memory.get("TEST_ANALYSIS_RESULTS.md")
-    : Read(".workflow/WFS-test-[id]/.process/TEST_ANALYSIS_RESULTS.md"),
+    : Read(".workflow/sessions/WFS-test-[id]/.process/TEST_ANALYSIS_RESULTS.md"),
 
-  test_context_package_path: ".workflow/WFS-test-[id]/.process/test-context-package.json",
+  test_context_package_path: ".workflow/sessions/WFS-test-[id]/.process/test-context-package.json",
 
   test_context_package: memory.has("test-context-package.json")
     ? memory.get("test-context-package.json")
-    : Read(".workflow/WFS-test-[id]/.process/test-context-package.json"),
+    : Read(".workflow/sessions/WFS-test-[id]/.process/test-context-package.json"),
 
   // Load source session summaries if exists
   source_session_id: session_metadata.source_session_id || null,
@@ -312,7 +312,7 @@ This section provides quick reference for test task JSON structure. For complete
 
 ## Output Files Structure
 ```
-.workflow/WFS-test-[session]/
+.workflow/sessions/WFS-test-[session]/
 ├── workflow-session.json           # Test session metadata
 ├── IMPL_PLAN.md                    # Test validation plan
 ├── TODO_LIST.md                    # Progress tracking