Include desktop app logs in diagnostics (#1914)

* fix(diagnostics): include desktop app logs

Settings diagnostics now collect the Electron main-process log separately from daemon.log so desktop startup and environment-probe failures are included in app reports.

* refactor(desktop): share log tail reader

* fix(diagnostics): surface desktop app log read errors

* refactor(diagnostics): tighten desktop report API

packages/desktop/src/daemon/daemon-manager.ts

@@ -39,6 +39,8 @@ import {
 import type { DesktopSettings } from "../settings/desktop-settings.js";
 import { getDesktopSettingsStore } from "../settings/desktop-settings-electron.js";
 import { isRunningUnderARM64Translation } from "../system/arm64-translation.js";
+import { getDesktopAppLogs } from "../diagnostics/app-logs.js";
+import { tailFile } from "../diagnostics/tail-file.js";
 
 const DAEMON_LOG_FILENAME = "daemon.log";
 const STARTUP_POLL_INTERVAL_MS = 200;
@@ -211,15 +213,6 @@ function sleep(ms: number): Promise<void> {
   });
 }
 
-function tailFile(filePath: string, lines = 50): string {
-  try {
-    const content = readFileSync(filePath, "utf-8");
-    return content.split("\n").filter(Boolean).slice(-lines).join("\n");
-  } catch {
-    return "";
-  }
-}
-
 function logDesktopDaemonLifecycle(message: string, details?: Record<string, unknown>): void {
   log.info("[desktop daemon]", message, {
     pid: process.pid,
@@ -574,6 +567,7 @@ export function createDaemonCommandHandlers(): Record<string, DesktopCommandHand
     stop_desktop_daemon: (args) => stopDesktopDaemon(parseDesktopDaemonStopReason(args)),
     restart_desktop_daemon: () => restartDaemon(),
     desktop_daemon_logs: () => getDaemonLogs(),
+    desktop_app_logs: () => getDesktopAppLogs(),
     desktop_daemon_pairing: () => getDaemonPairing(),
     desktop_get_system_idle_time: () => powerMonitor.getSystemIdleTime() * 1000,
     cli_daemon_status: () => getCliDaemonStatus(),