feat(console-update): systemd restart launcher for Linux supervision

Linux deployments under a systemd unit can now use the online update
panel: MULTI_SIMADMIN_SYSTEMD_UNIT (+ optional _SCOPE=user|system) hands
the restart to systemctl; createPlatformRestartLauncher picks launchd on
macOS and systemd on Linux, degrading to 'unsupported' otherwise.

apps/api/src/application/system/console-update-service.test.ts

@@ -6,6 +6,8 @@ import {
   ConsoleUpdateService,
   UpdateError,
   createLaunchdRestartLauncher,
+  createPlatformRestartLauncher,
+  createSystemdRestartLauncher,
   parseManifestVersion,
   parseShortStat,
   type UpdateCommandResult,
@@ -466,3 +468,73 @@ describe('createLaunchdRestartLauncher', () => {
     await expect(launcher.restart()).rejects.toMatchObject({ code: 'COMMAND', statusCode: 500 });
   });
 });
+
+describe('createSystemdRestartLauncher', () => {
+  it('is unsupported without a unit or with a malformed unit name', () => {
+    for (const unit of [undefined, '', 'evil; rm -rf /', 'multi-simadmin']) {
+      const launcher = createSystemdRestartLauncher({
+        env: unit === undefined ? {} : { MULTI_SIMADMIN_SYSTEMD_UNIT: unit },
+        runner: { run: async () => ({ code: 0, stdout: '', stderr: '' }) },
+      });
+      expect(launcher.supported).toBe(false);
+    }
+  });
+
+  it('restarts through the configured scope and unit', async () => {
+    const calls: string[][] = [];
+    const launcher = createSystemdRestartLauncher({
+      env: { MULTI_SIMADMIN_SYSTEMD_UNIT: 'multi-simadmin-api.service' },
+      runner: {
+        run: async (command, args) => {
+          calls.push([command, ...args]);
+          return { code: 0, stdout: '', stderr: '' };
+        },
+      },
+    });
+    expect(launcher.supported).toBe(true);
+    await launcher.restart();
+    expect(calls[0]).toEqual(['systemctl', 'user', 'restart', 'multi-simadmin-api.service']);
+  });
+
+  it('supports the system scope and surfaces systemctl failures', async () => {
+    const calls: string[][] = [];
+    const launcher = createSystemdRestartLauncher({
+      env: { MULTI_SIMADMIN_SYSTEMD_UNIT: 'multi-simadmin-api.service', MULTI_SIMADMIN_SYSTEMD_SCOPE: 'system' },
+      runner: {
+        run: async (command, args) => {
+          calls.push([command, ...args]);
+          return { code: 1, stdout: '', stderr: 'not logged in' };
+        },
+      },
+    });
+    await launcher.restart().catch(() => {});
+    expect(calls[0]).toEqual(['systemctl', 'system', 'restart', 'multi-simadmin-api.service']);
+    await expect(launcher.restart()).rejects.toMatchObject({ code: 'COMMAND', statusCode: 500 });
+  });
+});
+
+describe('createPlatformRestartLauncher', () => {
+  const runner = { run: async () => ({ code: 0, stdout: '', stderr: '' }) };
+
+  it('prefers systemd on Linux when a unit is configured', () => {
+    const launcher = createPlatformRestartLauncher({
+      env: { MULTI_SIMADMIN_HOST_PLATFORM: 'linux', MULTI_SIMADMIN_SYSTEMD_UNIT: 'api.service' },
+      runner,
+    });
+    expect(launcher.supported).toBe(true);
+  });
+
+  it('keeps the launchd launcher everywhere else', () => {
+    const linux = createPlatformRestartLauncher({
+      env: { MULTI_SIMADMIN_HOST_PLATFORM: 'linux' },
+      runner,
+    });
+    const darwin = createPlatformRestartLauncher({
+      env: { MULTI_SIMADMIN_HOST_PLATFORM: 'darwin', XPC_SERVICE_NAME: 'x' },
+      runner,
+      uid: () => 501,
+    });
+    expect(linux.supported).toBe(false);
+    expect(darwin.supported).toBe(true);
+  });
+});

apps/api/src/application/system/console-update-service.ts

@@ -241,6 +241,47 @@ export function createLaunchdRestartLauncher(input: {
   };
 }
 
+/**
+ * Linux systemd counterpart to the launchd launcher. The unit and scope are
+ * supplied explicitly through the environment so a supervised deployment can
+ * hand restarts to its service manager; unset variables keep it unsupported.
+ */
+export function createSystemdRestartLauncher(input: {
+  readonly env: Readonly<Record<string, string | undefined>>;
+  readonly runner: UpdateCommandRunner;
+}): RestartLauncher {
+  const unit = input.env.MULTI_SIMADMIN_SYSTEMD_UNIT ?? '';
+  const scope = input.env.MULTI_SIMADMIN_SYSTEMD_SCOPE === 'system' ? 'system' : 'user';
+  const validUnit = /^[A-Za-z0-9@_.\-]+\.service$/.test(unit);
+  const supported = validUnit;
+  return {
+    supported,
+    async restart() {
+      if (!supported)
+        throw new UpdateError('NOT_SUPPORTED', '未配置 systemd 服务单元（MULTI_SIMADMIN_SYSTEMD_UNIT）。', 501);
+      const result = await input.runner.run('systemctl', [scope, 'restart', unit]);
+      if (result.code !== 0)
+        throw new UpdateError(
+          'COMMAND',
+          text(result.stderr, 200) || 'systemctl restart 失败。',
+          500,
+        );
+    },
+  };
+}
+
+/** Picks the restart launcher matching the host service manager. */
+export function createPlatformRestartLauncher(input: {
+  readonly env: Readonly<Record<string, string | undefined>>;
+  readonly runner: UpdateCommandRunner;
+  readonly uid?: () => number | undefined;
+}): RestartLauncher {
+  const platform = input.env.MULTI_SIMADMIN_HOST_PLATFORM ?? process.platform;
+  return platform === 'linux' && input.env.MULTI_SIMADMIN_SYSTEMD_UNIT !== undefined
+    ? createSystemdRestartLauncher(input)
+    : createLaunchdRestartLauncher(input);
+}
+
 export interface ConsoleUpdateServiceOptions {
   readonly db: Database.Database;
   readonly version: string;