feat: strengthen module contracts and shared WebUI runtime

webui/src/platform/ModuleContext.tsx

@@ -1,4 +1,4 @@
-import { createContext, type ReactNode, useContext } from "react";
+import { createContext, type ReactNode, useContext, useMemo } from "react";
 import type { PlatformWebModule } from "../types";
 import { moduleInstalled, uiCapabilities, uiCapability } from "./modules";
 import { useEffectiveView, useViewSurfaces } from "./ViewContext";
@@ -19,22 +19,34 @@ export function usePlatformModuleInstalled(moduleId: string): boolean {
 }
 
 export function usePlatformUiCapability<T = unknown>(capabilityName: string): T | null {
-  return uiCapability<T>(capabilityName, useViewVisibleModules());
+  const modules = useViewVisibleModules();
+  return useMemo(
+    () => uiCapability<T>(capabilityName, modules),
+    [capabilityName, modules]
+  );
 }
 
 export function usePlatformUiCapabilities<T = unknown>(capabilityName: string): T[] {
-  return uiCapabilities<T>(capabilityName, useViewVisibleModules());
+  const modules = useViewVisibleModules();
+  return useMemo(
+    () => uiCapabilities<T>(capabilityName, modules),
+    [capabilityName, modules]
+  );
 }
 
 function useViewVisibleModules(): PlatformWebModule[] {
   const modules = usePlatformModules();
   const projection = useEffectiveView();
   const surfaces = useViewSurfaces();
-  return modules.filter((module) =>
-    isViewSurfaceVisible(
-      projection,
-      moduleViewSurfaceId(module.id),
-      surfaces
-    )
+  return useMemo(
+    () =>
+      modules.filter((module) =>
+        isViewSurfaceVisible(
+          projection,
+          moduleViewSurfaceId(module.id),
+          surfaces
+        )
+      ),
+    [modules, projection, surfaces]
   );
 }