refactor: Improve task granularity and reduce over-decomposition in workflow planning

- Increase complexity thresholds: Simple (≤8), Medium (9-15), Complex (>15) tasks
- Add core task granularity principles: function-based vs file-based decomposition
- Replace time-based merge conditions with clear functional criteria
- Update automatic decomposition threshold from >5 to >15 tasks
- Add comprehensive task pattern examples for better guidance
- Remove micro-task creation to improve workflow efficiency

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

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

.claude/commands/workflow/plan.md

@@ -68,12 +68,30 @@ The command automatically detects input type:
 - Generates session ID: WFS-[topic-slug]
 
 ### Complexity Detection with Saturation
-- **Simple**: <3 saturated tasks → Direct IMPL_PLAN.md
-- **Medium**: 3-8 saturated tasks → IMPL_PLAN.md + TODO_LIST.md
-- **Complex**: >8 saturated tasks → Full decomposition
+- **Simple**: ≤8 saturated tasks → Direct IMPL_PLAN.md
+- **Medium**: 9-15 saturated tasks → IMPL_PLAN.md + TODO_LIST.md
+- **Complex**: >15 saturated tasks → Full decomposition
 
 **Note**: 1 complex preparation task = 0.5 saturated task for counting
 
+### Task Granularity Principles
+- **按功能分解，不按文件分解**: 一个任务应该完成一个完整功能
+- **保持功能完整性**: 每个任务产出可独立运行或测试的功能单元
+- **相关组件一起实现**: UI、逻辑、测试等相关部分在同一任务中完成
+- **避免技术步骤分解**: 不要把"创建文件"、"添加函数"作为独立任务
+
+### 任务分解反模式
+❌ **错误示例 - 按文件/步骤分解**：
+- IMPL-001: 创建数据库模型
+- IMPL-002: 创建API端点
+- IMPL-003: 创建前端组件
+- IMPL-004: 添加路由配置
+- IMPL-005: 编写单元测试
+
+✅ **正确示例 - 按功能分解**：
+- IMPL-001: 实现用户认证功能（包含模型、API、UI、测试）
+- IMPL-002: 实现数据导出功能（包含处理逻辑、UI、文件生成）
+
 ### Task Generation with Saturation Control
 - **Task Saturation Assessment**: Evaluates whether to merge preparation and execution
 - **Default merge mode**: "Analyze and implement X" instead of "Analyze X" + "Implement X"
@@ -87,26 +105,29 @@ The command automatically detects input type:
 ### Task Saturation Assessment
 Evaluates whether to merge preparation and execution:
 
-**Merge Conditions** (Saturated Tasks):
-- Preparation work < 30min estimated
-- Analysis scope ≤ 3 files
-- No complex dependencies
-- Single module operation
+**默认合并原则** (Saturated Tasks):
+- 同一功能模块的所有组件
+- 前后端配套实现
+- 功能与其对应的测试
+- 配置与其使用的代码
+- 相互依赖的多个小功能
 
-**Separate Preparation Conditions**:
-- Cross-module architecture analysis (>5 modules)
-- Deep performance analysis or security audit required
-- Database migration design needed
-- Third-party API integration research
+**仅在以下情况分离任务**:
+- 完全独立的功能模块（无共享代码）
+- 不同技术栈的独立服务（如前端/后端分离部署）
+- 需要不同专业知识的模块（如ML模型训练 vs Web开发）
+- 有明确先后顺序依赖的大型功能
 
 **Task Examples**:
-- **Saturated**: "IMPL-001: Analyze auth patterns and implement JWT token management"
-- **Split needed**: "IMPL-001: Design cross-service auth architecture" + "IMPL-002: Implement auth service"
+- **合并示例**: "IMPL-001: 实现用户认证系统（包含JWT管理、API端点、UI组件和测试）"
+- **分离示例**: "IMPL-001: 设计跨服务认证架构" + "IMPL-002: 实现前端认证模块" + "IMPL-003: 实现后端认证服务"
 
 ### Task Breakdown Process
-- **Automatic decomposition**: Tasks with complexity >5 are broken into subtasks (impl-N.M format)
+- **Automatic decomposition**: Only when task count >15 are tasks broken into subtasks (impl-N.M format)
+- **Function-based decomposition**: Split by independent functional boundaries, not by technical layers
 - **Container tasks**: Parent tasks with subtasks become containers (marked with ▸ in TODO_LIST)
-- **Smart decomposition**: AI analyzes task title to suggest logical subtask structure
+- **Smart decomposition**: AI analyzes task title to suggest logical functional subtask structure
+- **Complete unit principle**: Each subtask must still represent a complete functional unit
 - **Context inheritance**: Subtasks inherit parent's requirements and scope, refined for specific needs
 - **Agent assignment**: Automatic agent mapping based on subtask type (planning/code/test/review)
 - **Maximum depth**: 2 levels (impl-N.M) to maintain manageable hierarchy
@@ -180,4 +201,21 @@ Generated in .task/ directory when decomposition enabled
   - Rejected examples: "do something", "fix it", "make it better", "add feature"
   - Response: Direct rejection message, no further assistance
 
-**System ensures**: Unified planning interface with intelligent input detection and automatic complexity handling
+### Recommended Task Patterns
+
+#### Complete Feature Implementation
+"Implement user management system" - includes CRUD operations, permissions, UI components, API endpoints, and tests
+
+#### End-to-End Features
+"Add Excel export functionality" - includes data processing, file generation, download API, UI buttons, and error handling
+
+#### System Integration
+"Integrate payment gateway" - includes API integration, order processing, payment flows, webhook handling, and testing
+
+#### Problem Resolution
+"Fix and optimize search functionality" - includes bug fixes, performance optimization, UI improvements, and related tests
+
+#### Module Development
+"Create notification system" - includes email/SMS sending, template management, subscription handling, and admin interface
+
+**System ensures**: Unified planning interface with intelligent input detection and function-based task granularity