feat: add retry/delete for jobs

- db.ts: add resetJob() and deleteJob() statements + exports
- pipeline.ts: export retryJob() — resets job state and re-runs pipeline
- DELETE /api/jobs/[id]: hard-delete terminal jobs (done/failed/cancelled);
  keep cancel-only behavior for active jobs
- POST /api/jobs/[id]/retry: new endpoint; validates failed/cancelled URL job,
  resets and re-runs via retryJob()
- jobs/[id]/+page.svelte: wire Cancel/Retry/Delete buttons with fetch calls;
  fix hardcoded ACCENT → accent store
- jobs/+page.svelte: per-row Retry+Delete icon buttons (visible on hover);
  fix hardcoded ACCENT → accent store

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/lib/server/db.ts

@@ -59,6 +59,15 @@ const stmts = {
 		UPDATE jobs SET status = @status, progress = @progress, updated_at = datetime('now')
 		WHERE id = @id
 	`),
+	resetJob: db.prepare(`
+		UPDATE jobs SET
+			status = 'pending', progress = 0, error = NULL,
+			mean_volume = NULL, whisper_job_id = NULL,
+			output_dir = NULL, segments_json = NULL,
+			updated_at = datetime('now')
+		WHERE id = @id
+	`),
+	deleteJob: db.prepare('DELETE FROM jobs WHERE id = ?'),
 	getJob: db.prepare('SELECT * FROM jobs WHERE id = ?'),
 	listJobs: db.prepare('SELECT * FROM jobs ORDER BY created_at DESC, rowid DESC LIMIT 100'),
 	upsertSub: db.prepare(`
@@ -135,3 +144,11 @@ export function getAllSubscriptions(): PushSubscription[] {
 export function deletePushSubscription(endpoint: string): void {
 	stmts.deleteSub.run(endpoint);
 }
+
+export function resetJob(id: string): void {
+	stmts.resetJob.run({ id });
+}
+
+export function deleteJob(id: string): void {
+	stmts.deleteJob.run(id);
+}