收口H5桥接载荷边界

让H5 HostBridge facade 复用共享MIME清单

增加原生壳门禁拦截H5本地复制MIME边界

补充共享决策记录中的载荷边界约定

scripts/check-native-shells.mjs

@@ -965,6 +965,52 @@ function assertH5HostBridgeEventSubscriptionGates() {
   }
 }
 
+function assertH5HostBridgePayloadBoundaries() {
+  const h5HostBridgeSource = fs.readFileSync(
+    'src/services/host-bridge/hostBridge.ts',
+    'utf8',
+  );
+
+  for (const sharedBoundary of [
+    'HOST_BRIDGE_TEXT_MIME_TYPES',
+    'HOST_BRIDGE_DOCUMENT_MIME_TYPES',
+    'HOST_BRIDGE_IMAGE_MIME_TYPES',
+    'HOST_BRIDGE_AUDIO_MIME_TYPES',
+  ]) {
+    if (!h5HostBridgeSource.includes(`${sharedBoundary},`)) {
+      throw new Error(
+        `H5 HostBridge facade must import shared payload boundary ${sharedBoundary}`,
+      );
+    }
+    if (new RegExp(`const ${sharedBoundary}\\s*=\\s*new Set`).test(h5HostBridgeSource)) {
+      throw new Error(
+        `H5 HostBridge facade must not redeclare shared payload boundary ${sharedBoundary}`,
+      );
+    }
+  }
+
+  for (const mimeLiteral of [
+    "'text/plain'",
+    "'text/markdown'",
+    "'text/csv'",
+    "'application/json'",
+    "'image/png'",
+    "'image/jpeg'",
+    "'image/webp'",
+    "'audio/mpeg'",
+    "'audio/mp4'",
+    "'audio/wav'",
+    "'audio/ogg'",
+    "'audio/webm'",
+  ]) {
+    if (h5HostBridgeSource.includes(mimeLiteral)) {
+      throw new Error(
+        `H5 HostBridge facade must read MIME boundaries from shared contract instead of ${mimeLiteral}`,
+      );
+    }
+  }
+}
+
 function extractDocumentCapabilityList(source, marker) {
   const markerIndex = source.indexOf(marker);
   if (markerIndex === -1) {
@@ -1613,6 +1659,9 @@ assertWechatMiniProgramCapabilityFlows();
 console.log('[check:native-shells] h5-host-bridge-event-subscription-gates');
 assertH5HostBridgeEventSubscriptionGates();
 
+console.log('[check:native-shells] h5-host-bridge-payload-boundaries');
+assertH5HostBridgePayloadBoundaries();
+
 console.log('[check:native-shells] production-shell-dev-scaffold-scan');
 assertNoProductionShellDevScaffoldTerms();