fix(offline): set the auto flag in setOfflineMode; remove temp diagnostic

The auto-offline -> online return was dead because setOfflineMode never set the
'auto' flag: I added the state + getter but forgot the assignment, so it stayed
false. So scheduleRecovery bailed immediately (no poll ran) and the online event's
'if (active && auto)' was false. The contour diagnostic confirmed offline.auto
stayed false after an auto-offline. Add 'auto = on && !persist'.

Also remove the temporary network diagnostic panel (netdiag + the lobby strip) --
it did its job of pinpointing this.

ui/src/lib/app.svelte.ts

@@ -57,7 +57,6 @@ import {
 import type { CoachSeries } from './coachmark';
 import { connection, reportOffline, reportOnline, resetConnection, checkReachable } from './connection.svelte';
 import { offlineMode, setOfflineMode } from './offline.svelte';
-import { netlog } from './netdiag.svelte'; // TEMP diagnostic
 import { shouldBootOffline } from './offline';
 import { isConnectionCode } from './retry';
 import { clearGameCache, getCachedGame, setCachedGame } from './gamecache';
@@ -604,15 +603,9 @@ export function scheduleRecovery(delayMs: number): void {
     recoveryTimer = null;
     if (!offlineMode.active || !offlineMode.auto) return;
     const interfaceUp = typeof navigator === 'undefined' || navigator.onLine;
-    netlog(`poll tick: navOnline=${interfaceUp}`); // TEMP diagnostic
-    if (interfaceUp) {
-      const reachable = await checkReachable(BOOT_REACHABILITY_TIMEOUT_MS);
-      netlog(`checkReachable=${reachable}`); // TEMP diagnostic
-      if (reachable && offlineMode.active && offlineMode.auto) {
-        setOfflineMode(false);
-        netlog('-> RETURNED ONLINE'); // TEMP diagnostic
-        return;
-      }
+    if (interfaceUp && (await checkReachable(BOOT_REACHABILITY_TIMEOUT_MS))) {
+      if (offlineMode.active && offlineMode.auto) setOfflineMode(false);
+      return;
     }
     scheduleRecovery(4000);
   }, delayMs);
@@ -621,17 +614,14 @@ export function scheduleRecovery(delayMs: number): void {
 export function initNetworkReactivity(): void {
   if (typeof window === 'undefined' || import.meta.env.MODE === 'mock') return;
   window.addEventListener('offline', () => {
-    netlog(`offline EVENT (active=${offlineMode.active})`); // TEMP diagnostic
     if (!offlineMode.active) {
       setOfflineMode(true, false); // auto (session)
-      netlog('-> auto-offline; poll started'); // TEMP diagnostic
       scheduleRecovery(4000); // poll for the network to return
     }
   });
   // The online event, when it fires, just kicks an immediate reachability check; the poll above is
   // the reliable fallback for platforms where it does not fire.
   window.addEventListener('online', () => {
-    netlog(`online EVENT (active=${offlineMode.active} auto=${offlineMode.auto})`); // TEMP diagnostic
     if (offlineMode.active && offlineMode.auto) scheduleRecovery(0);
   });
 }