merge: refresh hosting header verification contract

config/hosting/cache-policy.json

@@ -4,21 +4,25 @@
     "index": {
       "path": "/",
       "cacheControl": "no-cache",
+      "contentTypes": ["text/html"],
       "securityHeaders": true
     },
     "runtimeConfig": {
       "path": "/config.json",
       "cacheControl": "no-store",
+      "contentTypes": ["application/json"],
       "securityHeaders": true
     },
     "releaseManifest": {
       "path": "/release-manifest.json",
       "cacheControl": "no-store",
+      "contentTypes": ["application/json"],
       "securityHeaders": true
     },
     "hashedAsset": {
       "pathPattern": "/assets/*",
       "cacheControl": "public, max-age=31536000, immutable",
+      "contentTypes": ["text/javascript", "application/javascript"],
       "securityHeaders": false
     },
     "sourceMap": {

config/hosting/response-headers.fixture.json

@@ -3,6 +3,7 @@
   "responses": {
     "index": {
       "cache-control": "no-cache",
+      "content-type": "text/html; charset=utf-8",
       "content-security-policy": "default-src 'self'; base-uri 'self'; object-src 'none'; frame-ancestors 'none'; form-action 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; connect-src 'self' https:; font-src 'self'; upgrade-insecure-requests",
       "strict-transport-security": "max-age=31536000; includeSubDomains",
       "x-frame-options": "DENY",
@@ -12,6 +13,7 @@
     },
     "runtimeConfig": {
       "cache-control": "no-store",
+      "content-type": "application/json; charset=utf-8",
       "content-security-policy": "default-src 'self'; base-uri 'self'; object-src 'none'; frame-ancestors 'none'; form-action 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; connect-src 'self' https:; font-src 'self'; upgrade-insecure-requests",
       "strict-transport-security": "max-age=31536000; includeSubDomains",
       "x-frame-options": "DENY",
@@ -21,6 +23,7 @@
     },
     "releaseManifest": {
       "cache-control": "no-store",
+      "content-type": "application/json; charset=utf-8",
       "content-security-policy": "default-src 'self'; base-uri 'self'; object-src 'none'; frame-ancestors 'none'; form-action 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; connect-src 'self' https:; font-src 'self'; upgrade-insecure-requests",
       "strict-transport-security": "max-age=31536000; includeSubDomains",
       "x-frame-options": "DENY",
@@ -29,7 +32,8 @@
       "permissions-policy": "camera=(), microphone=(), geolocation=()"
     },
     "hashedAsset": {
-      "cache-control": "public, max-age=31536000, immutable"
+      "cache-control": "public, max-age=31536000, immutable",
+      "content-type": "text/javascript; charset=utf-8"
     }
   }
 }

docs/operations/release-cache-rollback.md

@@ -20,6 +20,10 @@ The provider-independent cache defaults are:
 - public source maps: disabled
 - service worker/offline cache: disabled
 
+HTML, JSON config/manifest, and hashed JavaScript MIME types are also compared
+to the declared allowlist; a cache-correct response with a mismatched
+`Content-Type` still fails the hosting gate.
+
 `corepack pnpm verify:hosting-headers` uses a deterministic fixture locally.
 Set `HOSTING_BASE_URL` to probe deployed responses; production promotion
 requires the artifact to report `mode: "live"`.

scripts/verify-hosting-headers.mjs

@@ -15,13 +15,13 @@ let mode;
 if (baseUrl) {
   mode = "live";
   const assets = await readdir("dist/assets");
-  const hashedAsset = assets.find((file) => !file.endsWith(".map"));
-  if (!hashedAsset) throw new Error("No built hashed asset found.");
+  const hashedJavaScript = assets.find((file) => file.endsWith(".js"));
+  if (!hashedJavaScript) throw new Error("No built hashed JavaScript found.");
   const paths = {
     index: "/",
     runtimeConfig: "/config.json",
     releaseManifest: "/release-manifest.json",
-    hashedAsset: `/assets/${hashedAsset}`,
+    hashedAsset: `/assets/${hashedJavaScript}`,
   };
   responses = {};
   for (const [surface, pathname] of Object.entries(paths)) {
@@ -51,6 +51,18 @@ for (const [surface, policy] of Object.entries(cachePolicy.surfaces)) {
     observed,
     passed: observed === policy.cacheControl,
   });
+  const observedContentType = responses[surface]?.["content-type"];
+  const observedMime = observedContentType
+    ?.split(";", 1)[0]
+    .trim()
+    .toLowerCase();
+  results.push({
+    surface,
+    header: "content-type",
+    expected: policy.contentTypes,
+    observed: observedContentType,
+    passed: policy.contentTypes.includes(observedMime),
+  });
   if (policy.securityHeaders) {
     for (const [header, expected] of Object.entries(securityPolicy.headers)) {
       const observedSecurity = responses[surface]?.[header.toLowerCase()];
@@ -100,7 +112,9 @@ await writeFile(
 );
 
 if (!passed) {
-  process.stderr.write("Hosting cache/security header verification failed.\n");
+  process.stderr.write(
+    "Hosting cache/content-type/security header verification failed.\n",
+  );
   process.exit(1);
 }
 process.stdout.write(