[Feature Request] Built-in Slash Command Descriptions Should Support Localization

Bug Description
ビルトインスラッシュコマンド（/branch, /clear, /compact等）の説明文が英語固定で、日本語に変更できない。language設定やカスタマイズで説明文をユーザー側で上書きできるようにしてほしい。

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.80
• Feedback ID: e1a4ed7f-ebc1-40ff-99f6-c38f485e0195

Errors

[{"error":"Error: 1: Command failed with ERR_STREAM_PREMATURE_CLOSE: code --force --install-extension anthropic.claude-code\nPremature close \n    at _TR (/$bunfs/root/src/entrypoints/cli.js:2731:4325)\n    at async t_R (/$bunfs/root/src/entrypoints/cli.js:2731:1730)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-20T15:03:11.333Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readSync (unknown)\n    at readSync (/$bunfs/root/src/entrypoints/cli.js:12:1534)\n    at d_q (/$bunfs/root/src/entrypoints/cli.js:103:434)\n    at tr (/$bunfs/root/src/entrypoints/cli.js:104:181)\n    at vP (/$bunfs/root/src/entrypoints/cli.js:106:54)\n    at _8$ (/$bunfs/root/src/entrypoints/cli.js:7341:8273)\n    at f (/$bunfs/root/src/entrypoints/cli.js:7341:7490)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:7341:7820)\n    at un (/$bunfs/root/src/entrypoints/cli.js:680:63126)\n    at pv_ (/$bunfs/root/src/entrypoints/cli.js:680:76226)","timestamp":"2026-03-20T15:30:02.411Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readSync (unknown)\n    at readSync (/$bunfs/root/src/entrypoints/cli.js:12:1534)\n    at d_q (/$bunfs/root/src/entrypoints/cli.js:103:434)\n    at tr (/$bunfs/root/src/entrypoints/cli.js:104:181)\n    at vP (/$bunfs/root/src/entrypoints/cli.js:106:54)\n    at _8$ (/$bunfs/root/src/entrypoints/cli.js:7341:8273)\n    at f (/$bunfs/root/src/entrypoints/cli.js:7341:7490)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:7341:7820)\n    at un (/$bunfs/root/src/entrypoints/cli.js:680:63126)\n    at pv_ (/$bunfs/root/src/entrypoints/cli.js:680:76226)","timestamp":"2026-03-20T15:30:14.060Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readSync (unknown)\n    at readSync (/$bunfs/root/src/entrypoints/cli.js:12:1534)\n    at d_q (/$bunfs/root/src/entrypoints/cli.js:103:434)\n    at tr (/$bunfs/root/src/entrypoints/cli.js:104:181)\n    at vP (/$bunfs/root/src/entrypoints/cli.js:106:54)\n    at _8$ (/$bunfs/root/src/entrypoints/cli.js:7341:8273)\n    at f (/$bunfs/root/src/entrypoints/cli.js:7341:7490)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:7341:7820)\n    at un (/$bunfs/root/src/entrypoints/cli.js:680:63126)\n    at pv_ (/$bunfs/root/src/entrypoints/cli.js:680:76226)","timestamp":"2026-03-20T15:39:41.932Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readSync (unknown)\n    at readSync (/$bunfs/root/src/entrypoints/cli.js:12:1534)\n    at d_q (/$bunfs/root/src/entrypoints/cli.js:103:434)\n    at tr (/$bunfs/root/src/entrypoints/cli.js:104:181)\n    at vP (/$bunfs/root/src/entrypoints/cli.js:106:54)\n    at _8$ (/$bunfs/root/src/entrypoints/cli.js:7341:8273)\n    at f (/$bunfs/root/src/entrypoints/cli.js:7341:7490)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:7341:7820)\n    at un (/$bunfs/root/src/entrypoints/cli.js:680:63126)\n    at pv_ (/$bunfs/root/src/entrypoints/cli.js:680:76226)","timestamp":"2026-03-20T15:45:44.183Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readSync (unknown)\n    at readSync (/$bunfs/root/src/entrypoints/cli.js:12:1534)\n    at d_q (/$bunfs/root/src/entrypoints/cli.js:103:434)\n    at tr (/$bunfs/root/src/entrypoints/cli.js:104:181)\n    at vP (/$bunfs/root/src/entrypoints/cli.js:106:54)\n    at _8$ (/$bunfs/root/src/entrypoints/cli.js:7341:8273)\n    at f (/$bunfs/root/src/entrypoints/cli.js:7341:7490)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:7341:7820)\n    at un (/$bunfs/root/src/entrypoints/cli.js:680:63126)\n    at pv_ (/$bunfs/root/src/entrypoints/cli.js:680:76226)","timestamp":"2026-03-20T15:45:48.128Z"},{"error":"Error: EISDIR: illegal operation on a directory, read '/Users/Ryo/Documents/Dev/ApplicationProjects/last-app/.claude'\n    at W$_ (/$bunfs/root/src/entrypoints/cli.js:927:8336)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-20T16:07:01.694Z"},{"error":"Error: EISDIR…

Note: Content was truncated.