Fixes an issue where evals were hitting "too many open files" errors
because we were adding (and detaching) new directory watches for each
project. Now we add those watches globally/at the worktree level, and we
store the tasks so they stop watching on drop.
Release Notes:
- N/A
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Co-authored-by: Max <max@zed.dev>
Co-authored-by: Piotr <piotr@zed.dev>
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>