fix(vom): add fixtures, remove fixed canvas numbers under budget, improve efficiency

apps/extension/src/session-manager/__tests__/ref-store.test.ts

@@ -77,4 +77,14 @@ describe("RefStore", () => {
     expect(s.resolveEntry("e1")?.capabilities).toEqual(["screenshot"]);
     expect(s.resolveEntry("e2")?.capabilities).toEqual(["screenshot"]);
   });
+
+  it("copies caller-owned capability arrays", () => {
+    const s = new RefStore();
+    const capabilities: Array<"interact" | "screenshot"> = ["screenshot"];
+    s.set("e1", 42, { tabId: 7, capabilities });
+
+    capabilities.push("interact");
+
+    expect(s.resolveEntry("e1")?.capabilities).toEqual(["screenshot"]);
+  });
 });

apps/extension/src/session-manager/ref-store.ts

@@ -45,7 +45,7 @@ function capabilitiesFor(
   capabilities: RefCapability[] | undefined,
 ): RefCapability[] {
   if (kind === "surface") return ["screenshot"];
-  return capabilities ?? ["interact", "screenshot"];
+  return capabilities ? [...capabilities] : ["interact", "screenshot"];
 }
 
 export class RefStore {