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/workflow-lite-planex/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: workflow-lite-planex
 description: Lightweight planning and execution skill (Phase 1: plan, Phase 2: execute). Triggers on "workflow-lite-planex".
-allowed-tools: Skill, Task, AskUserQuestion, TodoWrite, Read, Write, Edit, Bash, Glob, Grep
+allowed-tools: Skill, Agent, AskUserQuestion, TodoWrite, Read, Write, Edit, Bash, Glob, Grep
 ---
 
 # Workflow Lite-Planex

.claude/skills/workflow-lite-planex/phases/02-lite-execute.md

@@ -373,7 +373,7 @@ function executeBatch(batch) {
 
   if (executor === 'agent') {
     // Agent execution (synchronous)
-    return Task({
+    return Agent({
       subagent_type: "code-developer",
       run_in_background: false,
       description: batch.taskSummary,