Refactor chat session worktree handling and remove unused components (#312109)

* Refactor chat session worktree handling and remove unused components

Co-authored-by: Copilot <copilot@github.com>

* Updates

* Updates

* Updates

* Updats

Co-authored-by: Copilot <copilot@github.com>

* Updates

* Fixes

* Refactor session working directory management to use chat session metadata store

Co-authored-by: Copilot <copilot@github.com>

* Updates

Co-authored-by: Copilot <copilot@github.com>

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Co-authored-by: Copilot <copilot@github.com>