refactor(todos): remove internal file-based todo system (#635)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/skills/ce-work/SKILL.md

@@ -10,7 +10,7 @@ Execute work efficiently while maintaining quality and finishing features.
 
 ## Introduction
 
-This command takes a work document (plan, specification, or todo file) or a bare prompt describing the work, and executes it systematically. The focus is on **shipping complete features** by understanding requirements quickly, following existing patterns, and maintaining quality throughout.
+This command takes a work document (plan or specification) or a bare prompt describing the work, and executes it systematically. The focus is on **shipping complete features** by understanding requirements quickly, following existing patterns, and maintaining quality throughout.
 
 ## Input Document
 
@@ -22,7 +22,7 @@ This command takes a work document (plan, specification, or todo file) or a bare
 
 Determine how to proceed based on what was provided in `<input_document>`.
 
-**Plan document** (input is a file path to an existing plan, specification, or todo file) → skip to Phase 1.
+**Plan document** (input is a file path to an existing plan or specification) → skip to Phase 1.
 
 **Bare prompt** (input is a description of work, not a file path):
 
@@ -111,8 +111,8 @@ Determine how to proceed based on what was provided in `<input_document>`.
    - You want to keep the default branch clean while experimenting
    - You plan to switch between branches frequently
 
-3. **Create Todo List** _(skip if Phase 0 already built one, or if Phase 0 routed as Trivial)_
-   - Use your available task tracking tool (e.g., TodoWrite, task lists) to break the plan into actionable tasks
+3. **Create Task List** _(skip if Phase 0 already built one, or if Phase 0 routed as Trivial)_
+   - Use the platform's task tracking tool (`TaskCreate`/`TaskUpdate`/`TaskList` in Claude Code, `update_plan` in Codex, or the equivalent on other harnesses) to break the plan into actionable tasks
    - Derive tasks from the plan's implementation units, dependencies, files, test targets, and verification criteria
    - When the plan defines U-IDs for Implementation Units, preserve the unit's U-ID as a prefix in the task subject (e.g., "U3: Add parser coverage"). This keeps blocker references, deferred-work notes, and final summaries anchored to the same identifier the plan uses, so progress and traceability remain unambiguous across plan edits
    - Carry each unit's `Execution note` into the task when present