docs: Enhance target_files documentation and fix cross-platform command compatibility

## Target Files Enhancement
- Add support for new file creation in target_files format
- Update task-generate.md with comprehensive target_files generation guide
- Update concept-enhanced.md to output code modification targets
- Add examples showing both modification (file:function:lines) and creation (file) formats

## Cross-Platform Command Fixes
- Replace ls with find commands for better Windows Git Bash compatibility
- Update workflow commands: execute.md, status.md, review.md
- Update session commands: list.md, complete.md
- Add Bash environment guidelines to context-search-strategy.md
- Document forbidden Windows commands (findstr, dir, where, etc.)

## Files Updated
- Core workflows: workflow-architecture.md, task-core.md
- Command docs: 9 workflow command files
- Agent docs: action-planning-agent.md, task-generate-agent.md
- Strategy docs: context-search-strategy.md

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

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

.claude/agents/action-planning-agent.md

@@ -228,7 +228,7 @@ Generate individual `.task/IMPL-*.json` files with:
       "modification_points": ["Apply requirements"],
       "logic_flow": ["Load spec", "Analyze", "Implement", "Validate"]
     },
-    "target_files": ["file:function:lines"]
+    "target_files": ["file:function:lines", "path/to/NewFile.ts"]
   }
 }
 ```