refactor: replace Task tool with Agent tool and fix schema compliance

## Task -> Agent Replacement
- Replace all Task({}) calls with Agent({}) across .claude/ directory
- Update allowed-tools declarations from Task to Agent
- Update documentation references from "Task tool" to "Agent tool"

## Schema Compliance Fixes

### Agent Schema
- Add missing required `description` parameter in 6 files
- Add missing `run_in_background: false` for subagent calls
- Add missing `subagent_type` parameter

### AskUserQuestion Schema
- Fix issue-manage/SKILL.md: reduce options from 5 to 4 (max allowed)

### SendMessage Schema
- Fix team-worker.md: use correct params (type, content, summary)
- Remove invalid `team_name` parameter

### TaskCreate/TaskUpdate Schema
- Remove invalid `blockedBy`, `owner`, `status` from TaskCreate calls
- Use separate TaskUpdate calls for dependencies and ownership
- Fix TaskUpdate syntax to use object parameter

### TeamDelete Schema
- Remove parameters from TeamDelete() calls (should be no params)

### TaskOutput Schema
- Fix Python-style syntax to JavaScript object syntax

## Files Changed
- 146 files updated across commands/, skills/, skills_lib/, agents/

.claude/skills/skill-tuning/specs/skill-authoring-principles.md

@@ -114,18 +114,21 @@ Write(`${workDir}/final-output.json`, finalResult);  // 只存最终结果
 // 上下文流转模式
 async function executePhase(context) {
   const { previousResult, constraints, config } = context;
-  
-  const result = await Task({
+
+  const result = await Agent({
+    subagent_type: 'universal-executor',
+    description: 'Execute phase with context passing',
+    run_in_background: false,
     prompt: `
       [CONTEXT]
       Previous: ${JSON.stringify(previousResult)}
       Constraints: ${constraints.join(', ')}
-      
+
       [TASK]
       Process and return result directly.
     `
   });
-  
+
   return {
     ...context,
     currentResult: result,