fix(vfox): run pre_uninstall hook

[risu729]

Summary

• add the vfox PreUninstall hook binding and context
• run vfox tool plugin pre_uninstall hooks before removing install directories
• preserve dry-run behavior and skip the hook when the plugin itself is unavailable
• add crate and e2e regression coverage

Source

• VFox Tool Plugins Do Not Run Uninstall Hook #6154

Tests

• cargo test -p vfox
• mise run test:e2e e2e/backend/test_vfox_pre_uninstall

[greptile-apps]

Greptile Summary

This PR adds support for the vfox PreUninstall hook, which fires before the install directory is removed during mise uninstall. Dry-run mode and the case where the plugin is unavailable are both handled correctly.

• Adds crates/vfox/src/hooks/pre_uninstall.rs with PreUninstallContext and the Plugin::pre_uninstall executor, paralleling the existing post_install hook.
• Overrides uninstall_version_impl in src/backend/vfox.rs to call the hook only when the plugin is installed and not a backend plugin, with logging wired through the existing log_rx pattern.
• Adds unit and e2e tests that verify the marker file is written on a real uninstall and not written during a dry-run.

Confidence Score: 5/5

The change is self-contained: the new hook runs only when explicitly declared by the plugin, dry-run is preserved via the existing base-trait guard, and all new code follows established patterns in the vfox backend.

The hook execution is gated by a metadata check so plugins without pre_uninstall are unaffected. The dry-run guard lives in the base uninstall_version method, which is not modified here, so that invariant cannot regress. Error propagation from the hook correctly aborts the uninstall before directory removal. The unit test and e2e test together cover the happy path, the dry-run path, and the marker content.

No files require special attention.

_{Reviews (3): Last reviewed commit: "Merge branch 'main' into fix/vfox-pre-un..." | Re-trigger Greptile}

[gemini-code-assist]

Code Review

This pull request introduces a pre_uninstall hook for vfox plugins, allowing them to perform cleanup tasks before an SDK version is removed. The changes include the necessary Rust infrastructure to execute the hook, an update to the uninstall method to make it asynchronous, and the addition of unit and end-to-end tests. Feedback was provided regarding the uninstall method's transition to an asynchronous function, which represents a breaking change for the vfox crate API.