feat: add safe object copy and move actions

[cxymds]

Pull Request

Description

Add single-object Copy and Move actions to the object browser, with a destination bucket and full object path. Users can transfer an object between paths or buckets on the current server without downloading it.

• Protect existing destinations with conditional writes; validate paths without normalizing literal object keys.
• Use server-side multipart copy above 5 GiB, preserving source metadata and tags and cleaning up unfinished uploads on failure.
• For moves, confirm the copy, recheck the source, and then issue a conditional delete without deleting historical versions. Show explicit recovery guidance if source deletion fails or cannot be confirmed.
• Check source and exact destination permissions separately; provide progress, accessible field errors, bucket-list retry/manual entry, focus restoration, and mobile/dark-mode layouts.
• Add 52 regression tests and all 33 new messages across the 14 supported locales.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• Performance improvement
• Test improvements
• Security fix

Testing

• Unit tests added/updated
• Manual testing completed

All checks passed in an isolated worktree based on the latest main:

nvm use v22
pnpm install --frozen-lockfile
pnpm type-check
pnpm lint
pnpm format:check
pnpm test:run
pnpm build

• Full suite: 534 passed, 0 failed, including 52 new transfer/permission regression tests.
• Browser testing used the real UI and AWS SDK against a local mock S3 endpoint, covering cross-bucket Unicode keys, same-location validation, existing-target conflicts, successful moves, source-delete denial/partial success, bucket-list failure and retry, and a simulated 6 GiB multipart transfer.
• Checked progress/disabled controls, Escape prevention while running, keyboard focus restoration, 390 px mobile layout, and light/dark modes.
• Independent correctness/simplification, testing, and UX/i18n reviews completed. Live RustFS integration testing has not been performed.

Checklist

• Code follows the project's style guidelines
• Self-review completed
• TypeScript types are properly defined
• All commit messages are in English (Conventional Commits)
• All existing tests pass
• No new dependencies added, or they are justified

Related Issues

Implements the requested single-object copy/move workflow. No linked GitHub issue.

Screenshots (if applicable)

These are new dialogs, so there is no previous dialog to show as a before state. The after screenshots below use local fixture objects and a mock endpoint, not production data.

Desktop: destination form

Desktop: validation and destination-conflict states

Same-location validation:

Existing destination conflict, without overwriting:

Mobile: dark mode and recovery states

Dark-mode copy	Bucket suggestions unavailable	Copy succeeded; source deletion failed

Additional Notes

• Scope is one object on the current server; recursive folders, bulk transfers, and background-task integration are not included.
• A move is copy followed by conditional delete, not an atomic rename. Uncertain deletion is not automatically retried, and a confirmed copied destination is retained for recovery.
• The server must support the conditional S3 operations. Versioned sources and multipart tag preservation may require the corresponding version/tag read permissions in addition to the basic source/destination permissions.
• No backend changes or new dependencies are included.