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/team-ultra-analyze/role-specs/discussant.md

@@ -48,7 +48,7 @@ Select strategy by discussion type:
 
 **deepen**: Spawn cli-explore-agent focused on open questions and uncertain insights:
 ```
-Task({
+Agent({
   subagent_type: "cli-explore-agent",
   run_in_background: false,
   prompt: "Focus on open questions: <questions>. Find evidence for uncertain insights. Write to: <session>/discussions/deepen-<num>.json"
@@ -62,7 +62,12 @@ ccw cli -p "Re-analyze '<topic>' with adjusted focus on '<userFeedback>'" --tool
 
 **specific-questions**: Spawn cli-explore-agent targeting user's questions:
 ```
-Task({ subagent_type: "cli-explore-agent", prompt: "Answer: <userFeedback>. Write to: <session>/discussions/questions-<num>.json" })
+Agent({
+  subagent_type: "cli-explore-agent",
+  description: "Answer specific user questions",
+  run_in_background: false,
+  prompt: "Answer: <userFeedback>. Write to: <session>/discussions/questions-<num>.json"
+})
 ```
 
 ## Phase 4: Update Discussion Timeline