feat(sessions): Prefil mode-dropdown on new task screen based on previous tasks

[mp-hog]

Problem

Follow-up for #2712 (comment)

When you click "+" on a repo group in the Tasks sidebar, the new-task screen did not consider previous tasks.

Changes

• Derive a repo's most recent run environment from its visible tasks
• Open the new-task screen in that mode, the repo-selection resolver now takes the signal and picks Local/Cloud, preferring the repo's history over the global mode
• Carry the signal from the "+" click to the resolver, threaded through TaskListView → useOpenTask → prefill store → useAppView → TaskInput

How did you test this?

• Test cases
• Manually

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit c019968.}

[greptile-apps]

_{Reviews (1): Last reviewed commit: "Pass repo's run history from "+" to the ..." | Re-trigger Greptile}