Remove the API relay link and the ESP32 device feature

Two pieces of upstream promotion came out of this deployment.

The sidebar "apiRelay" tab only opened a registration page on a third-party
site, so it goes with no replacement.

The circuit badge next to Settings was not what it looked like. It opened an
ESP32 device manager: add a device, show LAN status, remote connect/disconnect,
rename, delete, backed by six REST routes and an mcu_devices table. The purchase
button inside that dialog was the promotional part; the rest was real device
management. Since the hardware is out of scope here, the entire feature is
removed rather than just the link that pointed upstream - UI entry, client API,
routes, controller, store, schema, locale strings, and the one GlobalAgentServer
method that only existed to answer its status column.

Table creation is dropped but no DROP TABLE was added, so an already-provisioned
database keeps its rows as harmless orphans instead of losing data on upgrade.

DevicesView and the hermes.devices route are untouched: that is LAN device
discovery, a separate feature.

AGENTS.md now records the removal so the badge does not come back.

packages/client/src/i18n/locales/en.ts

@@ -194,7 +194,6 @@ export default {
     chat: 'Chat',
     backToChat: 'Back',
     search: 'Search',
-    apiRelay: 'API Relay',
     history: 'History',
     jobs: 'Jobs',
     kanban: 'Kanban',
@@ -310,47 +309,6 @@ export default {
     },
   },
 
-  mcuDevices: {
-    title: 'Little Box',
-    subtitle: 'View device link status',
-    name: 'Name',
-    nameOptional: 'Name is optional',
-    deviceCode: 'Device code',
-    deviceCodePlaceholder: 'Enter device code',
-    deviceCodeRequired: 'Enter device code',
-    channel: 'Channel',
-    official: 'Official',
-    unofficial: 'Unofficial',
-    createdAt: 'Added at',
-    lanStatus: 'LAN',
-    remoteStatus: 'Remote',
-    connected: 'Connected',
-    disconnected: 'Disconnected',
-    remoteConnect: 'Remote connect',
-    remoteConnected: 'Remote connected',
-    remoteConnectFailed: 'Failed to connect remote',
-    remoteDisconnect: 'Disconnect',
-    remoteDisconnected: 'Remote disconnected',
-    remoteDisconnectFailed: 'Failed to disconnect remote',
-    actions: 'Actions',
-    add: 'Add',
-    addTitle: 'Add MCU device',
-    added: 'MCU device added',
-    addFailed: 'Failed to add MCU device',
-    purchase: 'Buy',
-    edit: 'Edit',
-    editNameTitle: 'Edit name',
-    nameUpdated: 'Name updated',
-    nameUpdateFailed: 'Failed to update name',
-    delete: 'Delete',
-    deleteTitle: 'Delete MCU device',
-    deleteConfirm: 'Delete "{name}"?',
-    deleted: 'MCU device deleted',
-    deleteFailed: 'Failed to delete MCU device',
-    loadFailed: 'Failed to load MCU devices',
-    close: 'Close',
-  },
-
   devices: {
     title: 'Devices',
     count: '{count} devices',

packages/client/src/i18n/locales/zh.ts

@@ -194,7 +194,6 @@ export default {
     chat: '对话',
     backToChat: '返回',
     search: '搜索',
-    apiRelay: '饲料',
     history: '历史',
     jobs: '任务',
     kanban: '看板',
@@ -310,47 +309,6 @@ export default {
     },
   },
 
-  mcuDevices: {
-    title: '小方盒',
-    subtitle: '查看设备链接状态',
-    name: '名称',
-    nameOptional: '名称可为空',
-    deviceCode: '设备码',
-    deviceCodePlaceholder: '请输入设备码',
-    deviceCodeRequired: '请输入设备码',
-    channel: '渠道',
-    official: '官方',
-    unofficial: '非官方',
-    createdAt: '添加时间',
-    lanStatus: '局域网',
-    remoteStatus: '远程',
-    connected: '已连接',
-    disconnected: '未连接',
-    remoteConnect: '远程连接',
-    remoteConnected: '远程已连接',
-    remoteConnectFailed: '远程连接失败',
-    remoteDisconnect: '断开连接',
-    remoteDisconnected: '远程已断开',
-    remoteDisconnectFailed: '远程断开失败',
-    actions: '操作',
-    add: '添加',
-    addTitle: '添加 MCU 设备',
-    added: 'MCU 设备已添加',
-    addFailed: '添加 MCU 设备失败',
-    purchase: '购买',
-    edit: '编辑',
-    editNameTitle: '编辑名称',
-    nameUpdated: '名称已更新',
-    nameUpdateFailed: '更新名称失败',
-    delete: '删除',
-    deleteTitle: '删除 MCU 设备',
-    deleteConfirm: '确定删除「{name}」吗？',
-    deleted: 'MCU 设备已删除',
-    deleteFailed: '删除 MCU 设备失败',
-    loadFailed: '加载 MCU 设备失败',
-    close: '关闭',
-  },
-
   devices: {
     title: '设备',
     count: '{count} 台设备',