refactor: Add tree-style execution flow diagrams to all workflow commands

Added tree-style execution process diagrams using ASCII art (├─, └─, │) to 34 workflow command files across three directories for improved readability and execution flow clarity.

## Changes by Directory

### workflow/ root (17 files)
- lite-plan.md, lite-execute.md, lite-fix.md
- plan.md, execute.md, replan.md
- status.md, review.md, review-fix.md
- review-session-cycle.md, review-module-cycle.md
- session commands (start, complete, resume, list)
- tdd-plan.md, tdd-verify.md, test-cycle-execute.md, test-gen.md, test-fix-gen.md

### workflow/ui-design/ (10 files)
- layout-extract.md, animation-extract.md, style-extract.md
- generate.md, import-from-code.md, codify-style.md
- imitate-auto.md, explore-auto.md
- reference-page-generator.md, design-sync.md

### workflow/tools/ (8 files)
- conflict-resolution.md, task-generate-agent.md, context-gather.md
- tdd-coverage-analysis.md, task-generate-tdd.md
- test-task-generate.md, test-concept-enhanced.md, test-context-gather.md

## Diagram Features
- Input parsing with flag enumeration
- Decision branching with conditional paths
- Phase/step hierarchy with clear nesting
- Mode detection and validation flows

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

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

.claude/commands/workflow/ui-design/generate.md

@@ -21,6 +21,36 @@ Pure assembler that combines pre-extracted layout templates with design tokens t
 - `/workflow:ui-design:style-extract` → Complete design systems (design-tokens.json + style-guide.md)
 - `/workflow:ui-design:layout-extract` → Layout structure
 
+## Execution Process
+
+```
+Input Parsing:
+   ├─ Parse flags: --design-id, --session
+   └─ Decision (base path resolution):
+      ├─ --design-id provided → Exact match by design ID
+      ├─ --session provided → Latest in session
+      └─ No flags → Latest globally
+
+Phase 1: Setup & Validation
+   ├─ Step 1: Resolve base path & parse configuration
+   ├─ Step 2: Load layout templates
+   ├─ Step 3: Validate design tokens
+   └─ Step 4: Load animation tokens (optional)
+
+Phase 2: Assembly (Agent)
+   ├─ Step 1: Calculate agent grouping plan
+   │  └─ Grouping rules:
+   │     ├─ Style isolation: Each agent processes ONE style
+   │     ├─ Balanced distribution: Layouts evenly split
+   │     └─ Max 10 layouts per agent, max 6 concurrent agents
+   ├─ Step 2: Launch batched assembly tasks (parallel)
+   └─ Step 3: Verify generated files
+
+Phase 3: Generate Preview Files
+   ├─ Step 1: Run preview generation script
+   └─ Step 2: Verify preview files
+```
+
 ## Phase 1: Setup & Validation
 
 ### Step 1: Resolve Base Path & Parse Configuration