Fold the sentinel into the scraper and drop the sentinel service (BL-0046)

The stall watchdog now runs inside the scraper (ScraperService.checkStalls,
every 30 s from the work loop): same rule as before, one checkpoint-safe
restart, quarantine on the second stall, missing checkpoint is no evidence,
and paused time no longer counts. Stalls are recorded as scraper incidents
(failure.kind 'stall'). The private /api/recovery endpoint is gone.

Dropped with the service: reader/scraper-unreachable incidents (supervisor
and Docker handle crashes; the health page shows "Scraper: unreachable"),
duplicate job-failure incidents and the unused /metrics endpoint.
The stack is now reader + scraper (+ optional peer-gateway).
The supervisor test moved to runtime/test (npm run test:runtime stays).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/services.test.js

@@ -24,23 +24,22 @@ test('three services integrate collections, auth, custom covers and private heal
       fs.writeFileSync(path.join(library, name, 'cover.png'), png);
       fs.writeFileSync(path.join(library, name, 'manga.json'), JSON.stringify({ title: name, tags: ['Fantasy'], status: 'ongoing' }));
     }
-    const [rp, sp, wp] = await Promise.all([port(), port(), port()]);
-    const base = `http://127.0.0.1:${rp}`, scraper = `http://127.0.0.1:${sp}`, sentinel = `http://127.0.0.1:${wp}`;
+    const [rp, sp] = await Promise.all([port(), port()]);
+    const base = `http://127.0.0.1:${rp}`, scraper = `http://127.0.0.1:${sp}`;
     const token = 'integration-test-only';
-    const env = { ...process.env, DATA: data, LIBRARY: library, SCRAPER_DATA: path.join(data, 'scraper'), SENTINEL_DATA: path.join(data, 'sentinel'),
-      PORT: String(rp), SCRAPER_PORT: String(sp), SENTINEL_PORT: String(wp), SCRAPER_HOST: '127.0.0.1', SENTINEL_HOST: '127.0.0.1',
-      READER_URL: base, SCRAPER_URL: scraper, SENTINEL_URL: sentinel, SCRAPER_TOKEN: token, SCRAPER_TOKEN_FILE: '', SCAN_INTERVAL: '0', COOKIE_SECURE: '0' };
-    for (const script of ['server.js', 'scraper/daemon.js', 'sentinel/daemon.js']) {
+    const env = { ...process.env, DATA: data, LIBRARY: library, SCRAPER_DATA: path.join(data, 'scraper'),
+      PORT: String(rp), SCRAPER_PORT: String(sp), SCRAPER_HOST: '127.0.0.1',
+      READER_URL: base, SCRAPER_URL: scraper, SCRAPER_TOKEN: token, SCRAPER_TOKEN_FILE: '', SCAN_INTERVAL: '0', COOKIE_SECURE: '0' };
+    for (const script of ['server.js', 'scraper/daemon.js']) {
       const child = spawn(process.execPath, [script], { cwd: root, env, windowsHide: true }); children.push(child);
       for (const stream of [child.stdout, child.stderr]) stream.on('data', chunk => output.push(chunk.toString()));
     }
-    for (const url of [base, scraper, sentinel]) {
+    for (const url of [base, scraper]) {
       let ready = false;
       for (let n = 0; n < 80 && !ready; n++) { ready = await fetch(url + '/health').then(r => r.ok).catch(() => false); if (!ready) await delay(100); }
       assert.ok(ready, output.join(''));
     }
     assert.equal((await fetch(scraper + '/api/state')).status, 401);
-    assert.equal((await fetch(sentinel + '/api/state')).status, 401);
     const signup = await fetch(base + '/api/signup', { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ name: 'tester', password: 'local-test-password' }) });
     assert.equal(signup.status, 200); const cookie = signup.headers.get('set-cookie').split(';')[0];
     const request = (endpoint, body) => fetch(base + endpoint, { headers: { cookie, 'content-type': 'application/json' }, ...(body ? { method: 'POST', body: JSON.stringify(body) } : {}) });
@@ -121,7 +120,7 @@ test('three services integrate collections, auth, custom covers and private heal
       const cover = await (await request('/api/admin/collection-cover', { id: 'demo', revision, base64: png.toString('base64') })).json(); revision = cover.revision;
       const image = await request('/api/collection-cover?id=demo'); assert.equal(image.status, 200); assert.deepEqual(Buffer.from(await image.arrayBuffer()), png);
     }
-    const health = await (await request('/api/admin/health')).json(); assert.ok(health.reader); assert.ok(health.sentinel);
+    const health = await (await request('/api/admin/health')).json(); assert.ok(health.reader); assert.equal(health.sentinel, undefined);
     assert.equal((await request('/api/admin/scraper')).status, 200);
     // Exercise the actual authenticated visit route and cross-chapter lease races.
     assert.equal((await request('/api/settings', { readingClock: true })).status, 200);