Update Todo tool hook to support new anthropic skills

[k11kirky]

"Anthropic replaced TodoWrite with 4 (actually 8 in the future) different skills.

That obviously will break our stuff. These PR attempt to fix that:
PostHog/wizard#471
PostHog/context-mill#141

There are some subtle behavior differences. The todoWrite updates aren't a single tool call anymore and the agent cannot maintain order of tasks. We need to give it a bit of help 🤷"

https://posthog.slack.com/archives/C09GTQY5RLZ/p1779490285886909

[gewenyu99]

Yes this is annoying. We might move to our own tools definition, but at the moment it become flaky and tries pretty hard to use its own new convention first, which is token waste 💢