feat: support macOS arm64 remote Agent hosts

Extend GoodBuddy Agent packaging, installation, SSH attachment, Runtime lifecycle, and Desktop package management to macOS arm64. Linux x64, Linux arm64, and Darwin arm64 share the existing signed catalog. Preserve Ask read-only behavior and Execute account permissions, and stop detached tool descendants during Mac cancellation.

Upgrade Desktop before publishing the first mixed-platform catalog because older Linux-only readers reject Darwin entries. Intel Macs are not supported; no launchd service or administrator access is required. This commit does not publish a release.

Validation: 3520 tests passed, 57 skipped; typecheck, lint, and development build passed. Real Mac installation, Ask/Execute, cancellation and reconnect passed; final Linux installation, Ask and reconnect passed. Nine real model requests were recorded.

Release note: 支持将 Apple Silicon Mac 用作远程项目 Host，可安装 macOS arm64 Agent 并使用 Ask、Execute 和断线重连；与 Linux 共用一个包目录，发布混合目录前需升级 Desktop。

src/agent-daemon/direct-linux-stdio-process-owner.ts

@@ -28,6 +28,7 @@ import {
   sameLinuxRuntimeProcessIdentity,
   type LinuxRuntimeProcessIdentity
 } from './runtime-process-identity'
+import { listDarwinProcessGroup, stopDarwinDescendants } from './darwin-process-identity'
 
 const DEFAULT_MAXIMUM_STDIN_WRITE_BYTES = 1024 * 1024
 const DEFAULT_MAXIMUM_OUTPUT_QUEUE_CHUNKS = 128
@@ -401,6 +402,9 @@ export class DirectLinuxStdioProcessOwner {
       throw identityError('Runtime PID identity changed before signal')
     }
     this.#registry.markStopping(this.ownerId)
+    if (process.platform === 'darwin') {
+      await stopDarwinDescendants(this.processIdentity.pid, Date.parse(deadlineAt))
+    }
     this.#stdinClosed = true
     this.#child.stdin.end()
     this.#sendSignal(-record.processIdentity.processGroupId, 'SIGTERM')
@@ -540,9 +544,9 @@ export class DirectLinuxStdioProcessOwner {
 export async function launchDirectLinuxStdioProcessOwner(
   options: DirectLinuxStdioProcessOwnerOptions
 ): Promise<DirectLinuxStdioProcessOwner> {
-  if ((options.platform ?? process.platform) !== 'linux') {
+  if (!['linux', 'darwin'].includes(options.platform ?? process.platform)) {
     throw new DirectLinuxStdioProcessOwnerError(
-      'Direct Runtime ownership is Linux-only',
+      'Direct Runtime ownership requires Linux or macOS',
       'platform'
     )
   }
@@ -786,6 +790,18 @@ export async function listLinuxPidNamespaceMembers(
   >,
   options: { procRoot?: string } = {}
 ): Promise<LinuxRuntimeProcessIdentity[]> {
+  if (process.platform === 'darwin') {
+    const identities: LinuxRuntimeProcessIdentity[] = []
+    for (const pid of listDarwinProcessGroup(owner.processGroupId)) {
+      try {
+        const identity = await readLinuxRuntimeProcessIdentity(pid, { bootId: owner.bootId })
+        if (identity.processGroupId === owner.processGroupId) identities.push(identity)
+      } catch (error) {
+        if (!isMissingProcess(error)) throw error
+      }
+    }
+    return identities.sort((left, right) => left.pid - right.pid)
+  }
   const procRoot = options.procRoot ?? '/proc'
   const entries = await readdir(procRoot, { withFileTypes: true })
   const identities: LinuxRuntimeProcessIdentity[] = []