fix(offline): gate library listing to downloaded-only when offline (#10)

The connectivity store now drives the "downloaded only" view so an
offline library page shows just on-device media, with the server catalog
revealed only when "Show all server media" is toggled.

TRACES: UR-052 | DR-078, DR-079

src/lib/services/offlineCatalog.test.ts

@@ -0,0 +1,94 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// UT-068: `pushCatalogVisibility` resolves `serverReachable || showCatalog` and
+// pushes the result to the backend whenever either input changes.
+// See docs/specs/offline-downloaded-only-filter.md (DR-078/DR-079).
+//
+// `isConnected` now tracks server reachability alone (DR-079), so from this
+// service's perspective its input is "is the server reachable". We drive it and
+// the `showServerCatalog` toggle and assert what gets pushed via
+// `commands.setShowServerCatalog`.
+
+const h = vi.hoisted(() => {
+  function shim<T>(initial: T) {
+    let value = initial;
+    const subs = new Set<(v: T) => void>();
+    return {
+      set(v: T) {
+        value = v;
+        subs.forEach((fn) => fn(value));
+      },
+      subscribe(fn: (v: T) => void) {
+        subs.add(fn);
+        fn(value);
+        return () => subs.delete(fn);
+      },
+    };
+  }
+  return {
+    isConnectedStore: shim(true),
+    setShowServerCatalog: vi.fn(async () => {}),
+  };
+});
+
+vi.mock("$lib/stores/connectivity", () => ({
+  isConnected: { subscribe: h.isConnectedStore.subscribe },
+}));
+
+vi.mock("$lib/api/bindings", () => ({
+  commands: {
+    setShowServerCatalog: h.setShowServerCatalog,
+    syncFullCatalog: vi.fn(),
+    resumeQueuedDownloads: vi.fn(),
+    catalogSyncStatus: vi.fn(),
+  },
+}));
+
+vi.mock("$lib/stores/auth", () => ({
+  auth: { getRepository: () => ({ getHandle: () => "handle-1" }) },
+}));
+
+describe("pushCatalogVisibility resolves reachable || showCatalog (UT-068)", () => {
+  beforeEach(() => {
+    h.setShowServerCatalog.mockClear();
+    h.isConnectedStore.set(true);
+    vi.resetModules();
+  });
+
+  it("pushes include=true while the server is reachable (initial subscribe)", async () => {
+    const { showServerCatalog } = await import("./offlineCatalog");
+    // Initial subscription with reachable=true, showCatalog=false ⇒ include=true.
+    expect(h.setShowServerCatalog).toHaveBeenLastCalledWith(true);
+    // Keep the import binding referenced so tree-shaking never elides it.
+    expect(showServerCatalog).toBeDefined();
+  });
+
+  it("pushes include=false when unreachable and the toggle is off", async () => {
+    h.isConnectedStore.set(false);
+    await import("./offlineCatalog");
+    // Fresh module subscribes with reachable=false, showCatalog=false ⇒ false.
+    expect(h.setShowServerCatalog).toHaveBeenLastCalledWith(false);
+  });
+
+  it("re-pushes include=true when the toggle flips on while unreachable", async () => {
+    h.isConnectedStore.set(false);
+    const { showServerCatalog } = await import("./offlineCatalog");
+    h.setShowServerCatalog.mockClear();
+
+    showServerCatalog.set(true); // showCatalog input changes ⇒ include flips to true
+    expect(h.setShowServerCatalog).toHaveBeenLastCalledWith(true);
+
+    h.setShowServerCatalog.mockClear();
+    showServerCatalog.set(false); // back off ⇒ include flips to false
+    expect(h.setShowServerCatalog).toHaveBeenLastCalledWith(false);
+  });
+
+  it("does not re-push when the resolved value is unchanged", async () => {
+    // reachable=true ⇒ include already true. Turning the toggle on keeps it true.
+    const { showServerCatalog } = await import("./offlineCatalog");
+    h.setShowServerCatalog.mockClear();
+
+    showServerCatalog.set(true); // include stays true (true || true) ⇒ no push
+    expect(h.setShowServerCatalog).not.toHaveBeenCalled();
+  });
+});

src/lib/services/offlineCatalog.ts

@@ -11,7 +11,7 @@
 // It also owns the `showServerCatalog` UI flag (the offline banner toggle that
 // reveals greyed-out, non-downloaded server media).
 //
-// TRACES: UR-002
+// TRACES: UR-002, UR-052 | DR-078
 
 import { writable, type Writable } from "svelte/store";
 import { commands } from "$lib/api/bindings";