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/pipeline.ts

@@ -1,4 +1,4 @@
-import { createJob, updateJob, setJobStatus, getJob } from './db.js';
+import { createJob, updateJob, setJobStatus, getJob, resetJob } from './db.js';
 import { downloadYouTube, saveUploadedFile, cleanupJobTmp } from './downloader.js';
 import { prepareAudio, cleanup as cleanupFiles } from './audio.js';
 import { submitJob, streamJob } from './whisper.js';
@@ -50,6 +50,16 @@ export async function startUploadJob(
 	return job.id;
 }
 
+/** Retry a failed/cancelled YouTube job by resetting and re-running the pipeline. */
+export async function retryJob(jobId: string): Promise<void> {
+	const job = getJob(jobId);
+	if (!job) throw new Error('Job not found');
+	resetJob(jobId);
+	runJob(jobId, { type: 'youtube', url: job.source }, job.audioMode as AudioMode).catch((err) => {
+		console.error(`[pipeline] retry job ${jobId} failed:`, err);
+	});
+}
+
 async function runJob(
 	jobId: string,
 	input: { type: 'youtube'; url: string } | { type: 'upload'; buffer: Buffer; filename: string },