Decouple stats daemon and preserve final mine OSD status

- Run `subminer stats -b` as a dedicated daemon process, independent from the overlay app
- Stop Anki progress spinner before showing final `✓`/`x` mine result so it is not overwritten
- Keep grammar/noise subtitle tokens hoverable while stripping annotation metadata

src/stats-daemon-entry.ts

@@ -0,0 +1,135 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { spawn } from 'node:child_process';
+import { shell } from 'electron';
+import { sanitizeStartupEnv } from './main-entry-runtime';
+import {
+  isBackgroundStatsServerProcessAlive,
+  readBackgroundStatsServerState,
+  removeBackgroundStatsServerState,
+  resolveBackgroundStatsServerUrl,
+} from './main/runtime/stats-daemon';
+import {
+  createRunStatsDaemonControlHandler,
+  type StatsDaemonControlArgs,
+} from './stats-daemon-control';
+import {
+  type StatsCliCommandResponse,
+  writeStatsCliCommandResponse,
+} from './main/runtime/stats-cli-command';
+
+const STATS_DAEMON_RESPONSE_TIMEOUT_MS = 12_000;
+
+function readFlagValue(argv: string[], flag: string): string | undefined {
+  for (let i = 0; i < argv.length; i += 1) {
+    const arg = argv[i];
+    if (!arg) continue;
+    if (arg === flag) {
+      const value = argv[i + 1];
+      if (value && !value.startsWith('--')) {
+        return value;
+      }
+      return undefined;
+    }
+    if (arg.startsWith(`${flag}=`)) {
+      return arg.split('=', 2)[1];
+    }
+  }
+  return undefined;
+}
+
+function hasFlag(argv: string[], flag: string): boolean {
+  return argv.includes(flag);
+}
+
+function parseControlArgs(argv: string[], userDataPath: string): StatsDaemonControlArgs {
+  return {
+    action: hasFlag(argv, '--stats-daemon-stop') ? 'stop' : 'start',
+    responsePath: readFlagValue(argv, '--stats-response-path'),
+    openBrowser: hasFlag(argv, '--stats-daemon-open-browser'),
+    daemonScriptPath: path.join(__dirname, 'stats-daemon-runner.js'),
+    userDataPath,
+  };
+}
+
+async function waitForDaemonResponse(responsePath: string): Promise<StatsCliCommandResponse> {
+  const deadline = Date.now() + STATS_DAEMON_RESPONSE_TIMEOUT_MS;
+  while (Date.now() < deadline) {
+    try {
+      if (fs.existsSync(responsePath)) {
+        return JSON.parse(fs.readFileSync(responsePath, 'utf8')) as StatsCliCommandResponse;
+      }
+    } catch {
+      // retry until timeout
+    }
+    await new Promise((resolve) => setTimeout(resolve, 100));
+  }
+
+  return {
+    ok: false,
+    error: 'Timed out waiting for stats daemon startup response.',
+  };
+}
+
+export async function runStatsDaemonControlFromProcess(userDataPath: string): Promise<number> {
+  const args = parseControlArgs(process.argv, userDataPath);
+  const statePath = path.join(userDataPath, 'stats-daemon.json');
+
+  const writeFailureResponse = (message: string): void => {
+    if (args.responsePath) {
+      try {
+        writeStatsCliCommandResponse(args.responsePath, {
+          ok: false,
+          error: message,
+        });
+      } catch {
+        // ignore secondary response-write failures
+      }
+    }
+  };
+
+  const handler = createRunStatsDaemonControlHandler({
+    statePath,
+    readState: () => readBackgroundStatsServerState(statePath),
+    removeState: () => {
+      removeBackgroundStatsServerState(statePath);
+    },
+    isProcessAlive: (pid) => isBackgroundStatsServerProcessAlive(pid),
+    resolveUrl: (state) => resolveBackgroundStatsServerUrl(state),
+    spawnDaemon: async (options) => {
+      const childArgs = [options.scriptPath, '--stats-user-data-path', options.userDataPath];
+      if (options.responsePath) {
+        childArgs.push('--stats-response-path', options.responsePath);
+      }
+      const logLevel = readFlagValue(process.argv, '--log-level');
+      if (logLevel) {
+        childArgs.push('--log-level', logLevel);
+      }
+      const child = spawn(process.execPath, childArgs, {
+        detached: true,
+        stdio: 'ignore',
+        env: {
+          ...sanitizeStartupEnv(process.env),
+          ELECTRON_RUN_AS_NODE: '1',
+        },
+      });
+      child.unref();
+      return child.pid ?? 0;
+    },
+    waitForDaemonResponse,
+    openExternal: async (url) => shell.openExternal(url),
+    writeResponse: writeStatsCliCommandResponse,
+    killProcess: (pid, signal) => {
+      process.kill(pid, signal);
+    },
+    sleep: async (ms) => new Promise((resolve) => setTimeout(resolve, ms)),
+  });
+
+  try {
+    return await handler(args);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    writeFailureResponse(message);
+    return 1;
+  }
+}