refactor: replace TodoWrite backup system with native Task tools

Claude Code's Task tools (TaskCreate, TaskUpdate, TaskList, TaskGet)
persist natively across context compaction without requiring hooks.

Removes:
- PreCompact hook (save-todowrite.sh)
- SessionStart hook (restore-todowrite.sh)
- Backup directory logic in .claude/backups/todowrite/

Updates:
- inject-session-instructions.sh: Reference TaskCreate instead of TodoWrite
- auto_learn_mistakes.py: Suggest TaskCreate instead of TodoWrite
- v2.0 STATE.md: Mark task-tools-integration completed

Task ID: v2.0-task-tools-integration

Author: cowwoc

.claude/cat/issues/v2/v2.0/STATE.md

@@ -70,9 +70,9 @@ Prepare CAT for commercial release with pricing tiers, license key system, and b
 - work-box-hook-precomputation
 - research-executive-summary
 - license-validation-server-jetty-setup
+- task-tools-integration
 
 ## Tasks Pending
-- task-tools-integration
 - split-retrospective-files-by-time
 - optimize-git-squash
 - move-planning-to-issues-subdir

.claude/cat/issues/v2/v2.0/task-tools-integration/STATE.md

@@ -1,6 +1,8 @@
 # State
 
-- **Status:** pending
-- **Progress:** 0%
+- **Status:** completed
+- **Progress:** 100%
+- **Resolution:** implemented
 - **Dependencies:** []
 - **Last Updated:** 2026-01-24
+- **Completed:** 2026-01-24

plugin/hooks/hooks.json

@@ -25,14 +25,6 @@
           }
         ]
       },
-      {
-        "hooks": [
-          {
-            "type": "command",
-            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/restore-todowrite.sh"
-          }
-        ]
-      },
       {
         "hooks": [
           {
@@ -68,16 +60,6 @@
         ]
       }
     ],
-    "PreCompact": [
-      {
-        "hooks": [
-          {
-            "type": "command",
-            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/save-todowrite.sh"
-          }
-        ]
-      }
-    ],
     "PreToolUse": [
       {
         "matcher": "AskUserQuestion",

plugin/hooks/inject-session-instructions.sh

@@ -44,7 +44,7 @@ MESSAGE=$(cat << 'INSTRUCTIONS'
 
 **When user input arrives mid-operation**:
 1. **STOP** current task analysis immediately
-2. Add to TodoWrite (all issues, even just 2-3 items)
+2. Track with TaskCreate if needed (all issues, even just 2-3 items)
 3. If impacts current task → address now; else → add to end
 4. Acknowledge before continuing
 

plugin/hooks/posttool_handlers/auto_learn_mistakes.py

@@ -48,16 +48,16 @@ def check(self, tool_name: str, tool_result: dict, context: dict) -> dict | None
             return None
 
         # Build suggestion
-        todowrite_content = f"LFM: Investigate {mistake_type} from {tool_name}"
-        todowrite_active = f"Investigating {mistake_type} mistake"
+        task_subject = f"LFM: Investigate {mistake_type} from {tool_name}"
+        task_active_form = f"Investigating {mistake_type} mistake"
 
         return {
             "additionalContext": f"""📚 MISTAKE DETECTED: {mistake_type}
 
-**MANDATORY**: Check TodoWrite for existing entry, add if not present:
-- content: "{todowrite_content}"
-- status: "pending"
-- activeForm: "{todowrite_active}"
+**MANDATORY**: Use TaskCreate to track this investigation:
+- subject: "{task_subject}"
+- description: "Investigate {mistake_type} detected during {tool_name} execution"
+- activeForm: "{task_active_form}"
 
 **Context**: Detected {mistake_type} during {tool_name} execution.
 **Details**: {mistake_details[:500] if mistake_details else 'N/A'}"""