test(api): DC-087 hermetic caddy-admin health mirrors + file-level raw-fetch guard [glm-grade=B]

Two mirrored health-handler test suites (health-endpoints, health-probe-aliases)
probed the Caddy admin API with raw Origin-less native fetch. On the prod host
the adversarial cron runs the full jest suite every 30 min against a live Caddy
admin with enforce_origin: 12 journal 403 lines per run (~700/day of
'client is not allowed to access from origin' spam) while tests stayed green.

- Mirrors now call fetchT (byte-identical to src/app.js:930 probe) with fetchT
  jest.spyOn-mocked at buildApp scope; caddyOk-configurable in both suites
- New guard test in utils-http-caddy-admin-origin.test.js: any __tests__ file
  pairing a raw await-fetch with a Caddy-admin token (:2019|adminUrl|
  CADDY_ADMIN) fails the suite — file-level pairing catches the historical
  cross-line drift shape a call-window regex missed
- DC-087-ALLOW-RAW-FETCH comment escape hatch (raw-text marker, guard file
  never self-exempts, skips logged to jest output)

Judge: GLM-5.3 cold read via delegate_task deleg_4d384dea (round 1 C -> round 2
B, zero blockers, polish folded). Verdict URN: urn:ump:azrv2xp72koiwi5r4yb6ureu4aqqloqq64sgmftsajh6ci2mzj2q
Mutation probes: historical drift reintroduction -> guard red; hatch marker ->
skipped+logged; restore -> 33/33. Full suite 2603/2603.

dashcaddy-api/__tests__/health-endpoints.test.js

@@ -26,6 +26,19 @@ jest.mock('dockerode', () => {
 function buildApp({ configOk = true, servicesOk = true, dockerOk = true, caddyOk = true } = {}) {
   process.env.MOCK_DOCKER_DOWN = dockerOk ? '0' : '1';
 
+  // DC-087 — mirror src/app.js faithfully: the caddy check goes through
+  // fetchT (which injects the Origin header Caddy's enforce_origin allowlist
+  // requires), and is MOCKED so the suite is hermetic — no live request to a
+  // real Caddy admin on :2019. The previous raw-`fetch` mirror sent an
+  // Origin-less probe to the LIVE admin whenever the full suite ran on the
+  // prod host (adversarial cron every 30 min): 12 journal 403 lines per run,
+  // ~700/day of `client is not allowed to access from origin ''` noise,
+  // plus a false checks.caddy.ok=false in the mirrored readiness payload.
+  const fetchT = jest.spyOn(require('../src/utils/http'), 'fetchT')
+    .mockImplementation(async () => (caddyOk
+      ? { ok: true, status: 200 }
+      : { ok: false, status: 403 }));
+
   const app = express();
   const config = {
     CONFIG_FILE: '/tmp/dc-test-config.json',
@@ -103,9 +116,13 @@ function buildApp({ configOk = true, servicesOk = true, dockerOk = true, caddyOk
       allOk = false;
     }
 
+    // DC-087 — mirror src/app.js exactly (fetchT, not raw fetch). fetchT is
+    // mocked at buildApp() scope, so this stays hermetic: no live probe to a
+    // real Caddy admin (the old raw-fetch mirror 403-spammed the prod journal
+    // every time the adversarial cron ran the full suite on this host).
     try {
       const caddyUrl = config.CADDY_ADMIN_URL || 'http://localhost:2019';
-      const response = await fetch(`${caddyUrl}/config/apps/http/servers/srv0/listen`, { signal: AbortSignal.timeout(10000) });
+      const response = await fetchT(`${caddyUrl}/config/apps/http/servers/srv0/listen`, {}, 10000);
       checks.caddy = { ok: response.ok, status: response.status };
       if (!response.ok) allOk = false;
     } catch (e) {