feat(runtime): establish miniapp kernel and sdk design

tauri/src/runtime/artifacts/artifact-content-cache.ts

@@ -0,0 +1,27 @@
+/**
+ * Host 所有的易失 Artifact 内容缓存。
+ *
+ * 它只保存已经通过 ArtifactState 接纳的宿主字节；内容不写入 Conversation Store，
+ * Agent 只能引用不透明 local_ref，不能直接填充或读取缓存。
+ *
+ * Host-owned volatile bytes for Artifact metadata already accepted by
+ * ArtifactState. This cache has no network, persistence, DOM or protocol
+ * dependency: an Agent can name an opaque ref but cannot populate or read it.
+ */
+export class ArtifactContentCache {
+  private readonly blobs = new Map<string, Blob>();
+
+  public put(localRef: string, content: Blob): boolean {
+    if (!opaqueRef(localRef) || content.size > 512 * 1024 * 1024) return false;
+    this.blobs.set(localRef, content);
+    return true;
+  }
+
+  public get(localRef: string): Blob | undefined { return this.blobs.get(localRef); }
+  public has(localRef: string | undefined): boolean { return Boolean(localRef && this.blobs.has(localRef)); }
+  public clear(): void { this.blobs.clear(); }
+}
+
+function opaqueRef(value: string): boolean {
+  return /^[A-Za-z0-9_.:-]{1,128}$/.test(value) && !/[\\/]/.test(value);
+}