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/brainstorm/api-designer.md

@@ -46,10 +46,10 @@ allowed-tools: Task(conceptual-planning-agent), TodoWrite(*), Read(*), Write(*)
 ### Phase 1: Session & Framework Detection
 ```bash
 # Check active session and framework
-CHECK: .workflow/.active-* marker files
+CHECK: find .workflow/sessions/ -name "WFS-*" -type d
 IF active_session EXISTS:
     session_id = get_active_session()
-    brainstorm_dir = .workflow/WFS-{session}/.brainstorming/
+    brainstorm_dir = .workflow/sessions/WFS-{session}/.brainstorming/
 
     CHECK: brainstorm_dir/guidance-specification.md
     IF EXISTS:
@@ -162,7 +162,7 @@ IF update_mode = "incremental":
 
 ### Output Files
 ```
-.workflow/WFS-[topic]/.brainstorming/
+.workflow/sessions/WFS-[topic]/.brainstorming/
 ├── guidance-specification.md          # Input: Framework (if exists)
 └── api-designer/
     └── analysis.md            # ★ OUTPUT: Framework-based analysis
@@ -181,7 +181,7 @@ IF update_mode = "incremental":
 Session detection and selection:
 ```bash
 # Check for active sessions
-active_sessions=$(find .workflow -name ".active-*" 2>/dev/null)
+active_sessions=$(find .workflow/sessions/ -name "WFS-*" -type d 2>/dev/null)
 if [ multiple_sessions ]; then
   prompt_user_to_select_session()
 else
@@ -280,7 +280,7 @@ TodoWrite tracking for two-step process:
 
 ### Output Location
 ```
-.workflow/WFS-{topic-slug}/.brainstorming/api-designer/
+.workflow/sessions/WFS-{topic-slug}/.brainstorming/api-designer/
 ├── analysis.md                 # Primary API design analysis
 ├── api-specification.md        # Detailed endpoint specifications (OpenAPI/Swagger)
 ├── data-contracts.md           # Request/response schemas and validation rules
@@ -531,7 +531,7 @@ Upon completion, update `workflow-session.json`:
       "api_designer": {
         "status": "completed",
         "completed_at": "timestamp",
-        "output_directory": ".workflow/WFS-{topic}/.brainstorming/api-designer/",
+        "output_directory": ".workflow/sessions/WFS-{topic}/.brainstorming/api-designer/",
         "key_insights": ["endpoint_design", "versioning_strategy", "data_contracts"]
       }
     }