fix(whisper): handle model warmup events

- Ignore backend model lifecycle webhooks so model warmup does not
  mark jobs done early
- Parse batched SSE messages and relay model load states during
  submit retries

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

src/tests/webhook.test.ts

@@ -106,6 +106,64 @@ describe('POST /api/webhook/[jobId] — job not found', () => {
 	});
 });
 
+// ── Ignore backend model lifecycle webhooks ─────────────────────────────────────
+
+describe('POST /api/webhook/[jobId] — non-job webhook payloads', () => {
+	it('ignores model_ready events sent to job webhooks', async () => {
+		mockGetJob.mockReturnValue(makeJob('job-model-ready'));
+
+		const res = await POST(
+			makeEvent('job-model-ready', {
+				type: 'model_ready',
+				loaded_at: new Date().toISOString()
+			}) as any
+		);
+
+		expect(res.status).toBe(200);
+		expect(await res.json()).toEqual({ ok: true, ignored: 'not_a_job_event' });
+		expect(mockSetJobStatus).not.toHaveBeenCalled();
+		expect(mockUpdateJob).not.toHaveBeenCalled();
+		expect(mockWriteOutputs).not.toHaveBeenCalled();
+		expect(mockSendNotification).not.toHaveBeenCalled();
+	});
+
+	it('ignores model_unloaded events sent to job webhooks', async () => {
+		mockGetJob.mockReturnValue(makeJob('job-model-unloaded'));
+
+		const res = await POST(
+			makeEvent('job-model-unloaded', {
+				type: 'model_unloaded',
+				unloaded_at: new Date().toISOString()
+			}) as any
+		);
+
+		expect(res.status).toBe(200);
+		expect(await res.json()).toEqual({ ok: true, ignored: 'not_a_job_event' });
+		expect(mockSetJobStatus).not.toHaveBeenCalled();
+		expect(mockUpdateJob).not.toHaveBeenCalled();
+		expect(mockWriteOutputs).not.toHaveBeenCalled();
+		expect(mockSendNotification).not.toHaveBeenCalled();
+	});
+
+	it('ignores payloads with invalid status values', async () => {
+		mockGetJob.mockReturnValue(makeJob('job-invalid-status'));
+
+		const res = await POST(
+			makeEvent('job-invalid-status', {
+				id: 'bogus-whisper-id',
+				status: 'model_ready',
+				segments: []
+			}) as any
+		);
+
+		expect(res.status).toBe(200);
+		expect(await res.json()).toEqual({ ok: true, ignored: 'not_a_job_event' });
+		expect(mockSetJobStatus).not.toHaveBeenCalled();
+		expect(mockUpdateJob).not.toHaveBeenCalled();
+		expect(mockWriteOutputs).not.toHaveBeenCalled();
+	});
+});
+
 // ── Local cancellation guard ──────────────────────────────────────────────────
 
 describe('POST /api/webhook/[jobId] — locally cancelled job', () => {