Add memory-viewer from silicondawn

- Web UI for browsing and editing OpenClaw memory files
- Cloned from https://github.com/silicondawn/memory-viewer
- Built and running on port 8901
- Features: file tree, markdown rendering, search, live reload
- Full access to MEMORY.md, daily notes, skills, automations

memory-viewer/public/sw.js

@@ -0,0 +1,60 @@
+const CACHE_NAME = 'memory-viewer-v1';
+const STATIC_ASSETS = ['/'];
+
+// Install: cache shell
+self.addEventListener('install', (e) => {
+  e.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => cache.addAll(STATIC_ASSETS))
+  );
+  self.skipWaiting();
+});
+
+// Activate: clean old caches
+self.addEventListener('activate', (e) => {
+  e.waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(keys.filter((k) => k !== CACHE_NAME).map((k) => caches.delete(k)))
+    )
+  );
+  self.clients.claim();
+});
+
+// Fetch: network-first for API, cache-first for assets
+self.addEventListener('fetch', (e) => {
+  const url = new URL(e.request.url);
+
+  // API calls: network only
+  if (url.pathname.startsWith('/api/') || url.pathname.startsWith('/ws')) {
+    return;
+  }
+
+  // Assets with hash in filename: cache-first (immutable)
+  if (url.pathname.startsWith('/assets/') && url.pathname.match(/\-[a-zA-Z0-9_-]{8}\./)) {
+    e.respondWith(
+      caches.match(e.request).then((cached) => {
+        if (cached) return cached;
+        return fetch(e.request).then((resp) => {
+          if (resp.ok) {
+            const clone = resp.clone();
+            caches.open(CACHE_NAME).then((cache) => cache.put(e.request, clone));
+          }
+          return resp;
+        });
+      })
+    );
+    return;
+  }
+
+  // HTML: network-first, fallback to cache
+  e.respondWith(
+    fetch(e.request)
+      .then((resp) => {
+        if (resp.ok) {
+          const clone = resp.clone();
+          caches.open(CACHE_NAME).then((cache) => cache.put(e.request, clone));
+        }
+        return resp;
+      })
+      .catch(() => caches.match(e.request))
+  );
+});