refactor(plugins): make runtime registry lazy

src/plugins/runtime.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, it } from "vitest";
 import { createEmptyPluginRegistry } from "./registry.js";
 import {
+  getActivePluginRegistry,
   pinActivePluginHttpRouteRegistry,
   releasePinnedPluginHttpRouteRegistry,
   resetPluginRuntimeStateForTest,
@@ -14,6 +15,12 @@ describe("plugin runtime route registry", () => {
     resetPluginRuntimeStateForTest();
   });
 
+  it("stays empty until a caller explicitly installs or requires a registry", () => {
+    resetPluginRuntimeStateForTest();
+
+    expect(getActivePluginRegistry()).toBeNull();
+  });
+
   it("keeps the pinned route registry when the active plugin registry changes", () => {
     const startupRegistry = createEmptyPluginRegistry();
     const laterRegistry = createEmptyPluginRegistry();

src/plugins/runtime.ts

@@ -17,7 +17,7 @@ const state: RegistryState = (() => {
   };
   if (!globalState[REGISTRY_STATE]) {
     globalState[REGISTRY_STATE] = {
-      registry: createEmptyPluginRegistry(),
+      registry: null,
       httpRouteRegistry: null,
       httpRouteRegistryPinned: false,
       key: null,
@@ -100,9 +100,8 @@ export function getActivePluginRegistryVersion(): number {
 }
 
 export function resetPluginRuntimeStateForTest(): void {
-  const emptyRegistry = createEmptyPluginRegistry();
-  state.registry = emptyRegistry;
-  state.httpRouteRegistry = emptyRegistry;
+  state.registry = null;
+  state.httpRouteRegistry = null;
   state.httpRouteRegistryPinned = false;
   state.key = null;
   state.version += 1;