feat(export): confirm bulk downloads

[flamboh]

What changed

• confirm album and library downloads before analytics, metadata writes, ZIP creation, or browser download
• show album-grouped counts and current-file byte estimates with expandable per-track details and explicit loose-track grouping
• keep single-track downloads immediate
• consolidate album/library execution into one target-driven pipeline
• revalidate complete export-affecting state before confirm, announce stale/unavailable changes, and require explicit reconfirmation
• guard double confirmation, busy dismissal, empty albums, and stale ready→unready transitions
• focus Cancel initially and restore focus to the initiating download control
• use bounded artwork fingerprints rather than serializing binary cover data
• add unit and Playwright interaction coverage

Why

Bulk downloads can include many files and significant data. This makes scope and estimated size inspectable without adding friction to single-track export.

Verification

• post-rebase bun run typecheck
• post-rebase bun run lint — 0 warnings/errors
• post-rebase bun run test — 65 files, 414 tests passed
• git diff --check
• two fresh independent reviews; all correctness, focus, stale-state, and performance findings fixed and re-reviewed

The Playwright interaction spec covers mounted focus, Escape/outside dismissal, restoration, and constrained mobile scrolling. It was typechecked but not executed because no server was already listening and repository instructions prohibit starting a dev server for this workflow.

This branch was rebased onto origin/main and is independently mergeable.

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit f8af51f.}

[cloudflare-workers-and-pages]

Deploying with    Cloudflare Workers

The latest updates on your project. Learn more about integrating Git with Workers.

Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	tagium	f8af51f	Commit Preview URL Branch Preview URL	Jul 23 2026, 04:56 AM

[flamboh]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat(audio): add waveform preview playback #127
• feat(ui): add mobile workspace navigation #125
• feat(export): confirm bulk downloads #123 👈 (View in Graphite)
• feat(metadata): reopen cleanup suggestions #121
• feat(ui): polish workspace states #120
• feat(metadata): add advanced editor #124
• feat(metadata): add advanced field policy #122
• refactor(audio): make formats explicit #119
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[flamboh]

Superseded by the clean export confirmation rebuild in #138.