feat(dev-workflow): Add intelligent backend selection based on task complexity (#61)

合并智能 backend 选择功能。包含：multiSelect backend 选择、type 字段任务分类(default|ui|quick-fix)、智能路由策略

dev-workflow/agents/dev-plan-generator.md

@@ -12,7 +12,7 @@ You are a specialized Development Plan Document Generator. Your sole responsibil
 
 You receive context from an orchestrator including:
 - Feature requirements description
-- codeagent analysis results (feature highlights, task decomposition, UI detection flag)
+- codeagent analysis results (feature highlights, task decomposition, UI detection flag, and task typing hints)
 - Feature name (in kebab-case format)
 
 Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
@@ -29,6 +29,7 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ### Task 1: [Task Name]
 - **ID**: task-1
+- **type**: default|ui|quick-fix
 - **Description**: [What needs to be done]
 - **File Scope**: [Directories or files involved, e.g., src/auth/**, tests/auth/]
 - **Dependencies**: [None or depends on task-x]
@@ -38,7 +39,7 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 ### Task 2: [Task Name]
 ...
 
-(2-5 tasks)
+(Tasks based on natural functional boundaries, typically 2-5)
 
 ## Acceptance Criteria
 - [ ] Feature point 1
@@ -53,9 +54,13 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Generation Rules You Must Enforce
 
-1. **Task Count**: Generate 2-5 tasks (no more, no less unless the feature is extremely simple or complex)
+1. **Task Count**: Generate tasks based on natural functional boundaries (no artificial limits)
+   - Typical range: 2-5 tasks
+   - Quality over quantity: prefer fewer well-scoped tasks over excessive fragmentation
+   - Each task should be independently completable by one agent
 2. **Task Requirements**: Each task MUST include:
    - Clear ID (task-1, task-2, etc.)
+   - A single task type field: `type: default|ui|quick-fix`
    - Specific description of what needs to be done
    - Explicit file scope (directories or files affected)
    - Dependency declaration ("None" or "depends on task-x")
@@ -67,18 +72,23 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Your Workflow
 
-1. **Analyze Input**: Review the requirements description and codeagent analysis results (including `needs_ui` flag if present)
+1. **Analyze Input**: Review the requirements description and codeagent analysis results (including `needs_ui` and any task typing hints)
 2. **Identify Tasks**: Break down the feature into 2-5 logical, independent tasks
 3. **Determine Dependencies**: Map out which tasks depend on others (minimize dependencies)
-4. **Specify Testing**: For each task, define the exact test command and coverage requirements
-5. **Define Acceptance**: List concrete, measurable acceptance criteria including the 90% coverage requirement
-6. **Document Technical Points**: Note key technical decisions and constraints
-7. **Write File**: Use the Write tool to create `./.claude/specs/{feature_name}/dev-plan.md`
+4. **Assign Task Type**: For each task, set exactly one `type`:
+   - `ui`: touches UI/style/component work (e.g., .css/.scss/.tsx/.jsx/.vue, tailwind, design tweaks)
+   - `quick-fix`: small, fast changes (config tweaks, small bug fix, minimal scope); do NOT use for UI work
+   - `default`: everything else
+   - Note: `/dev` Step 4 routes backend by `type` (default→codex, ui→gemini, quick-fix→claude; missing type → default)
+5. **Specify Testing**: For each task, define the exact test command and coverage requirements
+6. **Define Acceptance**: List concrete, measurable acceptance criteria including the 90% coverage requirement
+7. **Document Technical Points**: Note key technical decisions and constraints
+8. **Write File**: Use the Write tool to create `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Quality Checks Before Writing
 
 - [ ] Task count is between 2-5
-- [ ] Every task has all 6 required fields (ID, Description, File Scope, Dependencies, Test Command, Test Focus)
+- [ ] Every task has all required fields (ID, type, Description, File Scope, Dependencies, Test Command, Test Focus)
 - [ ] Test commands include coverage parameters
 - [ ] Dependencies are explicitly stated
 - [ ] Acceptance criteria includes 90% coverage requirement