feat(ui,api): strip board redesign - island, rail by day, context view, server search, vault graph

ui/src/lib/panel/cache.ts

@@ -0,0 +1,49 @@
+// A small keyed cache behind the panel: the conversation index and the
+// last threads land here so the next open paints before the network
+// answers. localStorage when it exists, memory otherwise.
+export interface PanelCache {
+  get: <T>(key: string) => T | null;
+  set: (key: string, value: unknown) => void;
+}
+
+const memory = new Map<string, string>();
+
+function storage(): Pick<Storage, "getItem" | "setItem" | "removeItem"> {
+  try {
+    if (typeof localStorage !== "undefined") {
+      return localStorage;
+    }
+  } catch {
+    /* sandboxed */
+  }
+  return {
+    getItem: (key) => memory.get(key) ?? null,
+    removeItem: (key) => {
+      memory.delete(key);
+    },
+    setItem: (key, value) => {
+      memory.set(key, value);
+    },
+  };
+}
+
+export function panelCache(prefix: string): PanelCache {
+  const store = storage();
+  return {
+    get<T>(key: string): T | null {
+      try {
+        const raw = store.getItem(`${prefix}:${key}`);
+        return raw ? (JSON.parse(raw) as T) : null;
+      } catch {
+        return null;
+      }
+    },
+    set(key: string, value: unknown): void {
+      try {
+        store.setItem(`${prefix}:${key}`, JSON.stringify(value));
+      } catch {
+        store.removeItem(`${prefix}:${key}`);
+      }
+    },
+  };
+}