fix: keep retiring cleanup across swaps

docs/.generated/plugin-sdk-api-baseline.sha256

@@ -1,2 +1,2 @@
-120e369c16fc57dd038a08ff4bbea3f436bbecb0572171923ad05f933903edae  plugin-sdk-api-baseline.json
-311eae09f9c5b6f2c5877d6e7661bec2c755bc22fcc4036e6eeda40e8668e418  plugin-sdk-api-baseline.jsonl
+783f2c0fa7ca9e72fbb553aaebc88a3ba0ec6820c39a373dcc648f95a49c340d  plugin-sdk-api-baseline.json
+f4cbb04f31648599ade2010ee67444ed6c22dd7e210f037bfaabfe8ea39021b4  plugin-sdk-api-baseline.jsonl

src/plugins/runtime.test.ts

@@ -218,7 +218,20 @@ describe("setActivePluginRegistry", () => {
     expect(listImportedRuntimePluginIds()).toEqual(["runtime-plugin"]);
   });
 
-  it("continues cleanup when the same active registry is refreshed", async () => {
+  it.each([
+    {
+      name: "same active registry is refreshed",
+      refresh(nextRegistry: ReturnType<typeof createEmptyPluginRegistry>) {
+        setActivePluginRegistry(nextRegistry);
+      },
+    },
+    {
+      name: "active registry advances again",
+      refresh() {
+        setActivePluginRegistry(createEmptyPluginRegistry());
+      },
+    },
+  ] as const)("continues cleanup when the $name", async ({ refresh }) => {
     let releaseFirstCleanup: (() => void) | undefined;
     let markFirstCleanupStarted!: () => void;
     let markSecondCleanupCalled!: () => void;
@@ -271,7 +284,7 @@ describe("setActivePluginRegistry", () => {
     setActivePluginRegistry(next);
     await waitForCleanupSignal(firstCleanupStarted, "first cleanup start");
 
-    setActivePluginRegistry(next);
+    refresh(next);
     releaseFirstCleanup?.();
 
     await waitForCleanupSignal(secondCleanupCalled, "second cleanup");

src/plugins/runtime.ts

@@ -74,10 +74,9 @@ async function cleanupPreviousPluginHostRegistry(params: {
   if (!nextRegistry || nextRegistry === params.previousRegistry) {
     return;
   }
-  // Async cleanup must not clear state after another registry becomes live.
-  // Re-activating the same registry refreshes caches, but it is still the same
-  // live cleanup target and must not abort the old registry cleanup.
-  const shouldCleanup = () => state.activeRegistry === nextRegistry;
+  // Async cleanup must not clear state for a registry that has been restored
+  // active, but later swaps should not strand cleanup for the retiring registry.
+  const shouldCleanup = () => state.activeRegistry !== params.previousRegistry;
   await cleanupReplacedPluginHostRegistry({
     cfg: getRuntimeConfig(),
     previousRegistry: params.previousRegistry,