feat(library): remove a track from the library without deleting the file

RemoveFromLibrary deletes the audio_files rows the way the scan's own
orphan cleanup does and records each path in excluded_paths. The
exclusion is not an enhancement: without it the next scan finds the
file, sees no row and imports it again, so the button undoes itself.

The soft scan compares files on disk against rows in the database, so
surveyAudioFiles and countAudioFiles both take the exclusion set —
otherwise an excluded path makes the two disagree forever and queues a
full scan on every launch. Deleting a row cascades to queue_tracks, so
the removal calls the same CompactQueue hook RemoveLibrary does.

Also lands the requested badge: library-status-indicator is a button
again where it can act, utils/library-status.ts states once what owning
and wanting mean, and the long-declared queued state finally has a
producer.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UDCbcCZQepnpSQYJ6SxxZm

.pi/skills/yellowjacket-dev/references/schema-change.md

@@ -5,7 +5,21 @@ chain got wrong, and when squashing is legitimate — is in `CLAUDE.md`
 under *Backend packages → database*. Read it once. This is the
 checklist.
 
-A schema change needs **two** files, not one:
+**A brand-new table needs one file, not two.** The rule below is about
+a *column added to a table that already exists*. `applySchema` runs
+every file in `sql/schemas/` on every open, so a
+`CREATE TABLE IF NOT EXISTS` reaches an existing install verbatim and a
+migration for it would be a second description of the same table — the
+thing the third rule forbids. Its indexes go in the schema file too,
+because the column and the index arrive together.
+
+A new table has a second gate: **`backend/datamap`**. Add an entry
+stating its Kind and Lifetime, or `TestCatalogCoversSchema` fails — and
+if it is `Authored` and cascades, `TestAuthoredCascadesAreDeliberate`
+wants an explicit exemption with a note, because authored data is what
+a user cannot get back.
+
+Adding a **column** to an existing table needs **two** files, not one:
 
 1. **`backend/database/sql/schemas/*.sql`** — `CREATE TABLE ... IF NOT
    EXISTS`, the literal target shape, what sqlc reads and what a fresh