[Feature]: Native file-system watcher via the notify crate with targeted refresh events

[matiaspalmac]

Describe the feature

The explorer has no file watcher: external changes are only picked up when the user hits refresh or the git poll fires (every 5s). GitExplorerComponent.tsx:131-160 auto-reveals by reloading each parent directory, with no memoization.

Proposed feature:

1. Add a Rust watcher via the notify crate, scoped to the workspace, with debounce ~200 ms.
2. Emit typed events to the frontend (file-changed, file-created, file-deleted, dir-changed) with exact paths.
3. The frontend updates only the affected nodes and skips full re-walks.
4. Exclude node_modules, .git, target, .next and the user's filesExclude from the watched set.

Would you like to implement this feature yourself by sending a PR?

Maybe