refactor: migrate delegate_task to task tool with metadata fixes

- Rename delegate_task tool to task across codebase (100 files)
- Update model references: claude-opus-4-6 → 4-5, gpt-5.3-codex → 5.2-codex
- Add tool-metadata-store to restore metadata overwritten by fromPlugin()
- Add session ID polling for BackgroundManager task sessions
- Await async ctx.metadata() calls in tool executors
- Add ses_ prefix guard to getMessageDir for performance
- Harden BackgroundManager with idle deferral and error handling
- Fix duplicate task key in sisyphus-junior test object literals
- Fix unawaited showOutputToUser in ast_grep_replace
- Fix background=true → run_in_background=true in ultrawork prompt
- Fix duplicate task/task references in docs and comments

src/hooks/category-skill-reminder/index.ts

@@ -30,9 +30,8 @@ const DELEGATABLE_WORK_TOOLS = new Set([
  * Tools that indicate the agent is already using delegation properly.
  */
 const DELEGATION_TOOLS = new Set([
-  "delegate_task",
-  "call_omo_agent",
-  "task",
+   "task",
+   "call_omo_agent",
 ])
 
 function formatSkillNames(skills: AvailableSkill[], limit: number): string {
@@ -63,7 +62,7 @@ function buildReminderMessage(availableSkills: AvailableSkill[]): string {
     "> User-installed skills OVERRIDE built-in defaults. ALWAYS prefer YOUR SKILLS when domain matches.",
     "",
     "```typescript",
-    `delegate_task(category=\"visual-engineering\", load_skills=${loadSkills}, run_in_background=true)`,
+    `task(category=\"visual-engineering\", load_skills=${loadSkills}, run_in_background=true)`,
     "```",
     "",
   ]