feat: add DDD scan, sync, and update commands for document indexing

- Implemented `/ddd:scan` command to analyze existing codebases and generate document indices without specifications. This includes phases for project structure analysis, component discovery, feature inference, and requirement extraction.
- Introduced `/ddd:sync` command for post-task synchronization, updating document indices, generating action logs, and refreshing feature/component documentation after development tasks.
- Added `/ddd:update` command for lightweight incremental updates to the document index, allowing for quick impact checks during development and pre-commit validation.
- Created `execute.md` for the coordinator role in the team lifecycle, detailing the spawning of executor team-workers for IMPL tasks.
- Added `useHasHydrated` hook to determine if the Zustand workflow store has been rehydrated from localStorage, improving state management reliability.

.claude/commands/ddd/update.md

@@ -0,0 +1,154 @@
+---
+name: update
+description: Incremental index update - detect code changes and trace impact to related features/requirements. Lightweight alternative to full sync.
+argument-hint: "[-y|--yes] [--files <file1,file2,...>] [--staged] [--check-only]"
+allowed-tools: TodoWrite(*), AskUserQuestion(*), Read(*), Grep(*), Glob(*), Bash(*), Edit(*), Write(*), mcp__ace-tool__search_context(*)
+---
+
+## Auto Mode
+
+When `--yes` or `-y`: Auto-update index without confirmation prompts.
+
+# DDD Update Command (/ddd:update)
+
+## Purpose
+
+Lightweight incremental update: given a set of changed files, trace their impact through the document index and update affected entries. Unlike `/ddd:sync` (full post-task sync), this command focuses on keeping the index fresh during development.
+
+## When to Use: update vs sync
+
+| Scenario | Use |
+|----------|-----|
+| Quick impact check during development | **ddd:update** |
+| Preview what sync would change | **ddd:update --check-only** |
+| Task completed, full reconciliation | ddd:sync |
+| Register new components + update all docs | ddd:sync |
+
+**Rule of thumb**: `update` = lightweight pulse (during work), `sync` = full checkpoint (after work).
+
+## Use Cases
+
+1. **During development**: Quick check which docs are affected by current changes
+2. **Pre-commit check**: Ensure index is up-to-date before committing
+3. **Periodic refresh**: Update stale code locations after refactoring
+
+## Prerequisite
+
+- `doc-index.json` must exist at `.workflow/.doc-index/doc-index.json`
+
+## Phase 1: Identify Changed Files
+
+### Source Priority
+
+```
+1. --files <list>      → Explicit file list
+2. --staged            → git diff --cached --name-only
+3. (default)           → git diff --name-only (unstaged changes)
+```
+
+### Output
+
+List of changed file paths with change type (added/modified/deleted/renamed).
+
+## Phase 2: Trace Impact
+
+### 2.1 Forward Lookup (Code → Components → Features)
+
+For each changed file:
+
+```
+doc-index.json.technicalComponents[]
+  .codeLocations[].path MATCH changed_file
+  → component_ids[]
+
+doc-index.json.technicalComponents[component_ids]
+  .featureIds[]
+  → feature_ids[]
+
+doc-index.json.features[feature_ids]
+  .requirementIds[]
+  → requirement_ids[]
+```
+
+### 2.2 Orphan Detection
+
+Files not matching any component → flag as:
+- **Potential new component**: if in src/ directory
+- **Ignorable**: if in test/, docs/, config/ directories
+
+### 2.3 Impact Report
+
+```
+Impact Analysis for 3 changed files:
+
+  src/services/auth.ts (modified)
+    → Component: tech-auth-service (AuthService)
+    → Feature: feat-auth (User Authentication)
+    → Requirements: REQ-001, REQ-002
+
+  src/middleware/rate-limit.ts (added)
+    → No matching component (new file)
+    → Suggested: Register as new component
+
+  src/utils/hash.ts (modified)
+    → Component: tech-hash-util
+    → Features: feat-auth, feat-password-reset
+    → Requirements: REQ-001, REQ-005
+```
+
+## Phase 3: Update Index (unless --check-only)
+
+### 3.1 Update Code Locations
+
+For matched components:
+- If file was renamed → update `codeLocations[].path`
+- If file was deleted → remove code location entry
+- If symbols changed → update `symbols` list (requires AST or Gemini analysis)
+
+### 3.2 Register New Components (interactive unless -y)
+
+For orphan files in src/:
+- Prompt user for component name and type
+- Or auto-generate with `-y`: derive name from file path
+- Create `technicalComponents[]` entry
+- Ask which feature it belongs to (or auto-link by directory structure)
+
+### 3.3 Update Timestamps
+
+- Update `technicalComponents[].docPath` last_updated in corresponding .md
+- Update `doc-index.json.last_updated`
+
+## Phase 4: Refresh Documents (if updates were made)
+
+### 4.1 Minimal Doc Updates
+
+Only update documents that need changes:
+- `tech-registry/{slug}.md` — if code locations changed
+- `feature-maps/{slug}.md` — only if component list changed
+- `_index.md` files — only if entries were added/removed
+
+### 4.2 Skip If --check-only
+
+With `--check-only`, only output the impact report without modifying any files.
+
+## Flags
+
+| Flag | Effect |
+|------|--------|
+| `-y, --yes` | Auto-confirm updates |
+| `--files <list>` | Explicit comma-separated file list |
+| `--staged` | Analyze staged (git cached) files |
+| `--check-only` | Report impact without modifying index |
+
+## Output
+
+- **Console**: Impact report showing affected features/requirements
+- **Updated**: `doc-index.json` (if not --check-only)
+- **Updated**: Affected tech-registry/ and feature-maps/ docs
+
+## Integration Points
+
+- **Input from**: Git working tree, `doc-index.json`
+- **Output to**: Updated `doc-index.json`, impact report
+- **Triggers**: During development, pre-commit, or periodic refresh
+- **Can chain to**: `/ddd:sync` for full post-task synchronization