[wow]

Summary

The app can now export. The rail gets an Export section and button; the button first shows what the engine plans for each file, with nothing written until it is confirmed; rows walk through their stages and end with what was verified, the grid check and Revert; the footer links the batch's rekordbox XML and report. The pipeline machine gains export states, with one job at a time and the analysis queue as it was.

Exports go to a folder by default; in place with a backup is an explicit choice. Exporting again to a folder replaces a copy of this same file that SoundCheck wrote there, when its sidecar proves it, and one folder has one rekordbox XML and report that describe it. What the user confirms is what gets written: settings that changed refuse the job, and a file that changed fails its row before anything is written.

User-visible behaviour

• Rail, Export section: Prepare | Library; To folder (default, with a remembered folder) | In place with backup; depth source / 16 / 24; Grid only; Write TBPM (per mode); Write rekordbox XML. A file with Serato data makes the batch Library with a notice; choosing Prepare is remembered per folder.
• Export button (also in the top bar of a narrow window): disabled with its reason during a job, a revert or recovery, or when tracks were analysed under another BPM range ("3 tracks need Analyse for this BPM range"). With a folder all that is missing, "Choose a folder" opens the picker, and so does the top bar's Export.
• Confirm step: what is being typed reaches the engine first. Title and button say what is written ("Write 10 files"). 12 files: 9 gain, 3 cut, 2 skipped; backups in ~/Music/SoundCheck Backups, the target and ceiling, a warning when a cut shifts positions, "3 files replace your earlier copies", "1 file in the folder isn't SoundCheck's, skipped", "1 file skipped: a copy of another track already has its name", and what the folder's XML keeps. An XML or report there that starts like SoundCheck's but cannot be read whole refuses the export, naming the file.
• Rows exported with other settings say so ("Exported at -11.0"), and the confirm step says "18 exported at -11.0 stay as they are" with an unticked "Export them again at -8.0". A skipped row makes no work: a skip about the file itself stays, and any other is planned again and written only if the plan now differs.
• Rows: Queued, Processing, Writing, Checking (already verified), then Done, verified / Skipped / Failed. Action: Gain -2.3 dB, Cut 0.21 s with a positions-shift badge, Grid only, Grid: XML only (MP3). A row exported fine whose grid still asks for a look says Done, verified with the reason under it and counts in Needs review only, so the tabs add up.
• After export: "Verified: 27/27 carried, 3 added", the grid-check chip (an advisory is neutral, never a warning), Revert with a spinner on its row. Selecting a row shows the whole story under the table.
• Footer: progress and Cancel; links that show the XML, report and folder in the Finder; a "rekordbox XML" button that lists every analysed row, an exported copy where it is; an XML listing nothing says so plainly.
• Reload during an export: the export stops, the rows in flight keep their stage while the page waits, the links and summary come back, and a file written in place whose analysis did not finish is analysed again. After a minute the app says to restart.
• A file changed after it was analysed or confirmed says so on its row and to press Analyse, which is lit for it.
• sc-cli process requires --out <dir> or --in-place, refusing in three lines with exit 2 otherwise.
• The rows of a running batch cannot be reverted or opened until it ends. Rejected commands keep their typed error instead of [object Object].

Tests run

PASS  file-size               11s
PASS  test-files               0s
PASS  cargo-fmt                1s
PASS  cargo-clippy             2s
PASS  cargo-test             288s
PASS  fe-typecheck             4s
PASS  fe-lint                  4s
PASS  fe-test                 11s
RESULT PASS

New UI tests cover the rail, the machine, the store for every event, all Action kinds and chip states, the footer, the actions, what the Export button works on, the typed target landing before planning, and a whole export through <App /> on the stand-in. New Rust tests: src-tauri/src/shell/tests/preview.rs, crates/sc-io/src/txn/copy_at/tests.rs, the XML and report round trips and merges in crates/sc-engine/src/export/artefacts/tests.rs, copies replaced and refused in crates/sc-engine/tests/process.rs, and sc-cli process refusing and replacing. Every guard was broken on purpose (72 UI and 46 Rust breakages) and a test failed for each.

A browser pass on the stand-in found overflowReport() empty at 720x560 in idle, confirm, during and done.

Output change

• No: the same input still yields the same numbers, grids and bytes.
• Yes: goldens regenerated and reviewed; the commit carries Output-Change: yes; this ships in a minor release. No golden changed. A copy to a folder can now replace an earlier one, and a batch's rekordbox XML and grid report now merge with what SoundCheck wrote in that folder, sorted by location.

Docs and dependencies

• docs/PRODUCT.md / docs/ARCHITECTURE.md updated if behaviour or crate boundaries changed.
• New dependencies, with licence: none.

Output-Change: yes
BREAKING CHANGE: sc-cli process requires --out <dir> or --in-place.