Offline UX: network failures show quiet 'offline, n queued' not errors; auto-sync on connectivity regain + 45s heartbeat

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/src/lib/store.ts

@@ -18,6 +18,8 @@ export interface State {
   hydrated: boolean;
   syncing: boolean;
   pending: number;
+  /** True when the last sync failed for network reasons — expected offline. */
+  offline: boolean;
   syncError: string | null;
 }
 
@@ -34,6 +36,7 @@ let state: State = {
   hydrated: false,
   syncing: false,
   pending: 0,
+  offline: false,
   syncError: null,
 };
 let queue: Op[] = [];
@@ -193,9 +196,13 @@ export async function sync() {
       setState({});
     }
     await pull();
-    setState({ syncError: null });
+    setState({ syncError: null, offline: false });
   } catch (e) {
-    setState({ syncError: e instanceof Error ? e.message : String(e) });
+    const msg = e instanceof Error ? e.message : String(e);
+    // fetch() network failures (airplane mode, no wifi, DNS) are the expected
+    // offline case, not an error — the queue simply waits for connectivity.
+    const isNetwork = e instanceof TypeError || /network request failed|unable to resolve|fetch failed|timeout/i.test(msg);
+    setState(isNetwork ? { offline: true, syncError: null } : { syncError: msg });
   } finally {
     syncRunning = false;
     setState({ syncing: false });