feat: enhance workflow planning with concept clarification and agent delegation

🎯 Major Enhancements:

1. Concept Clarification Quality Gate (concept-clarify.md)
   - Added dual-mode support: brainstorm & plan modes
   - Auto-detects mode based on artifact presence (ANALYSIS_RESULTS.md vs synthesis-specification.md)
   - Backward compatible with existing brainstorm workflow
   - Updates appropriate artifacts based on detected mode

2. Planning Workflow Enhancement (plan.md)
   - Added Phase 3.5: Concept Clarification as quality gate
   - Integrated Phase 3.5 between analysis and task generation
   - Enhanced with interactive Q&A to resolve ambiguities
   - Updated from 4-phase to 5-phase workflow model
   - Delegated Phase 3 (Intelligent Analysis) to cli-execution-agent
   - Autonomous context discovery and enhanced prompt generation

3. Documentation Updates (README.md, README_CN.md)
   - Added /workflow:test-cycle-execute command documentation
   - Explained dynamic task generation and iterative fix cycles
   - Included usage examples and key features
   - Updated both English and Chinese versions

🔧 Technical Details:
- concept-clarify now supports both ANALYSIS_RESULTS.md (plan) and synthesis-specification.md (brainstorm)
- plan.md Phase 3 now uses cli-execution-agent for MCP-powered context discovery
- Maintains auto-continue mechanism with one interactive quality gate (Phase 3.5)
- All changes preserve backward compatibility

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

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

.claude/commands/workflow/tools/concept-enhanced.md

@@ -137,6 +137,8 @@ Advanced solution design and feasibility analysis engine with parallel CLI execu
 
 3. **Parallel Execution**: Launch tools simultaneously, monitor progress, handle completion/errors, maintain logs
 
+   **⚠️ IMPORTANT**: CLI commands MUST execute in foreground (NOT background). Do NOT use `run_in_background` parameter for Gemini/Codex execution.
+
 ### Phase 4: Results Collection & Synthesis
 1. **Output Validation**: Validate gemini-solution-design.md (all), codex-feasibility-validation.md (complex), use logs if incomplete, classify status
 2. **Quality Assessment**: Verify design rationale, insight depth, feasibility rigor, optimization value