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.test.ts

@@ -50,7 +50,7 @@ describe("category-skill-reminder hook", () => {
 
       // then - reminder should be injected
       expect(output.output).toContain("[Category+Skill Reminder]")
-      expect(output.output).toContain("delegate_task")
+      expect(output.output).toContain("task")
 
       clearSessionAgent(sessionID)
     })
@@ -130,16 +130,16 @@ describe("category-skill-reminder hook", () => {
   })
 
   describe("delegation tool tracking", () => {
-    test("should NOT inject reminder if delegate_task is used", async () => {
-      // given - sisyphus agent that uses delegate_task
+    test("should NOT inject reminder if task is used", async () => {
+      // given - sisyphus agent that uses task
       const hook = createHook()
       const sessionID = "delegation-session"
       updateSessionAgent(sessionID, "Sisyphus")
 
       const output = { title: "", output: "result", metadata: {} }
 
-      // when - delegate_task is used, then more tool calls
-      await hook["tool.execute.after"]({ tool: "delegate_task", sessionID, callID: "1" }, output)
+      // when - task is used, then more tool calls
+      await hook["tool.execute.after"]({ tool: "task", sessionID, callID: "1" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "2" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "3" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "4" }, output)
@@ -329,15 +329,15 @@ describe("category-skill-reminder hook", () => {
     })
 
     test("should handle delegation tool names case-insensitively", async () => {
-      // given - sisyphus agent using DELEGATE_TASK in uppercase
+      // given - sisyphus agent using TASK in uppercase
       const hook = createHook()
       const sessionID = "case-delegate-session"
       updateSessionAgent(sessionID, "Sisyphus")
 
       const output = { title: "", output: "result", metadata: {} }
 
-      // when - DELEGATE_TASK in uppercase is used
-      await hook["tool.execute.after"]({ tool: "DELEGATE_TASK", sessionID, callID: "1" }, output)
+      // when - TASK in uppercase is used
+      await hook["tool.execute.after"]({ tool: "TASK", sessionID, callID: "1" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "2" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "3" }, output)
       await hook["tool.execute.after"]({ tool: "edit", sessionID, callID: "4" }, output)

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)`,
     "```",
     "",
   ]