[BUG] todowrite list goes stale for several turns, stays stuck on one item, and leaks the previous task's todos when switching to a new task

Description

On the desktop app, the todo list (todowrite tool) frequently does not update for many turns:

• It stays stuck on one item (often marked in_progress) even though the agent has moved far past it.
• When the user switches to a different task (or even continues a new path in the same session), the old task's todo list remains displayed and the agent keeps referencing it, instead of resetting/initializing a fresh todo for the new task.
• Toggling between tasks: the todo shown in the TUI sidebar does not reflect the current activity at all for long stretches (several turns / many minutes).

This makes the todo feature untrustworthy as progress indicator, and (more importantly) it is a real confusion for the agent itself, since it looks at the todos and thinks they still describe the current job.

Repro (Desktop)

1. Start a multi-step task with a todo list (5-6 items).
2. Let the agent work; after 2-3 turns the todo list shows only 1 item "in_progress" that is stale — the agent has since done later steps (edits, tests).
3. Ask a new, unrelated prompt: "now write tests for X" — the old todo list still displayed (previous task items), agent picks up old list or doesn't create a new one.
4. The todo list only refreshes after the agent happens to call todowrite again, or never, until user manually prompts.

Expected

• The agent should refresh the todo list every turn (or at least after each completed step / before/after tool-heavy operations), per current turn.
• When the user's new prompt starts a different task (detectable by "first user message after task complete" or on /reset or when the user asks something not covered by existing todos), the todo list should be reset/archived and a new one started.
• The UI should mark when todos correspond to an older task (e.g. stale display) rather than silently keeping them.

Related

• #22288 (closed: todo hang) — this is the stale/never-updated variant persisting into desktop.
• #27560 (closed: model completes but doesn't mark todo) — part of the same UX: the model rarely refreshes.

Suggestion for fix

Make the todos a first-class part of the agent loop: after every turn (or at least after any tool that mutates files), the agent receives the prompt/context include "your current todo list is stale, update it if needed" or a lifecycle hook that auto-updates. For task switch, an explicit "/todo reset" or automatic detection.

Reference to the current doc: the todowrite tool should be treated as part of the contract: every task change must update todos the same turn (like the checklist in TDD skill wfh.com).