Closes #55728

## Summary

The Windows installer writes the localized Windows 11 Explorer context
menu title to `HKCU\Software\Classes\{RegValueName}ContextMenu`, where
the release channels use `Zed`, `ZedPreview`, and `ZedNightly` as the
registry value names.

`explorer_command_injector.dll` was reading from `ZedEditor*ContextMenu`
instead, so the registry lookup failed and Explorer always received the
hardcoded `Open with Zed` fallback. This aligns the DLL registry paths
with the installer-written keys for stable, preview, and nightly.

## Tests

- `cargo check --package explorer_command_injector --no-default-features
--features stable`
- `cargo check --package explorer_command_injector --no-default-features
--features preview`
- `cargo check --package explorer_command_injector`
- `cargo check --package explorer_command_injector --all-features`
- `cargo fmt --check --package explorer_command_injector`
- `git diff --check`

Release Notes:

- Fixed localized Windows Explorer context menu titles falling back to
English.

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Co-authored-by: MrSubidubi <finn@zed.dev>