feat: add Network Backup section to Database Management

PC2 can now automatically pull and restore a fresh copy of PC1's database
on a daily schedule. Config and API key are stored in local JSON files so
they survive database restores.

- New networkSyncConfigService: file-based config (network-backup-key.json,
  network-sync-config.json) that persists through DB restores
- New networkSyncService: streams live pg_dump from source PC over HTTP and
  pipes into psql, then reconnects Prisma and applies missing migrations
- 6 new endpoints: get/regenerate API key, serve backup stream (key-auth
  only), get/save sync config, trigger immediate sync
- Hourly cron job that fires only when current hour matches configured syncHour
- NetworkBackupManager component: shows this machine's key (show/copy/regen)
  and receiver config (enable toggle, hour picker 0-23, source URL + key,
  Save + Sync Now, last sync status)
- README setup guide for both PCs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/Backend/src/cron/backupCheck.ts

@@ -4,6 +4,8 @@ import path from "path";
 import { storage } from "../storage";
 import { backupDatabaseToPath } from "../services/databaseBackupService";
 import { cronJobLogStorage } from "../storage/cron-job-log-storage";
+import { readSyncConfig, writeSyncConfig } from "../services/networkSyncConfigService";
+import { runNetworkSync } from "../services/networkSyncService";
 
 // Local backup folder in the app root (apps/Backend/backups)
 const LOCAL_BACKUP_DIR = path.resolve(process.cwd(), "backups");
@@ -171,4 +173,40 @@ export const startBackupCron = () => {
 
     console.log("✅ [9 PM] USB backup complete.");
   });
+
+  // ============================================================
+  // Every hour — Network sync (runs only when hour matches config)
+  // ============================================================
+  cron.schedule("0 * * * *", async () => {
+    const config = readSyncConfig();
+    if (!config.enabled || !config.sourceUrl || !config.apiKey) return;
+
+    const currentHour = new Date().getHours();
+    if (currentHour !== config.syncHour) return;
+
+    console.log(`🔄 [${config.syncHour}:00] Running network sync from ${config.sourceUrl}...`);
+
+    const admin = await getAdminUser();
+    const startedAt = new Date();
+    const log = await cronJobLogStorage.createJobLog("network-sync", startedAt);
+
+    try {
+      await runNetworkSync(config.sourceUrl, config.apiKey);
+      writeSyncConfig({ lastSyncAt: new Date().toISOString(), lastSyncStatus: "success", lastSyncError: null });
+      await cronJobLogStorage.completeJobLog(log.id, "success", new Date());
+      console.log(`✅ Network sync complete.`);
+    } catch (err) {
+      const errorMessage = err instanceof Error ? err.message : String(err);
+      console.error("Network sync failed:", err);
+      writeSyncConfig({ lastSyncAt: new Date().toISOString(), lastSyncStatus: "failed", lastSyncError: errorMessage });
+      await cronJobLogStorage.completeJobLog(log.id, "failed", new Date(), errorMessage);
+      if (admin) {
+        await storage.createNotification(
+          admin.id,
+          "BACKUP",
+          `❌ Network sync failed: ${errorMessage}`
+        );
+      }
+    }
+  });
 };