feat(web): Add centered empty state messages to pipeline extension dialogs (#1784)

* Initial plan

* feat: add empty state messages in pipeline extension dialogs

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* fix: center empty state messages in dialog content area

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

web/src/i18n/locales/en-US.ts

@@ -482,6 +482,8 @@ const enUS = {
       addMCPServer: 'Add MCP Server',
       selectMCPServers: 'Select MCP Servers',
       toolCount: '{{count}} tools',
+      noPluginsInstalled: 'No installed plugins',
+      noMCPServersConfigured: 'No configured MCP servers',
     },
     debugDialog: {
       title: 'Pipeline Chat',

web/src/i18n/locales/ja-JP.ts

@@ -485,6 +485,8 @@ const jaJP = {
       addMCPServer: 'MCPサーバーを追加',
       selectMCPServers: 'MCPサーバーを選択',
       toolCount: '{{count}}個のツール',
+      noPluginsInstalled: 'インストールされているプラグインがありません',
+      noMCPServersConfigured: '設定されているMCPサーバーがありません',
     },
     debugDialog: {
       title: 'パイプラインのチャット',

web/src/i18n/locales/zh-Hans.ts

@@ -464,6 +464,8 @@ const zhHans = {
       addMCPServer: '添加 MCP 服务器',
       selectMCPServers: '选择 MCP 服务器',
       toolCount: '{{count}} 个工具',
+      noPluginsInstalled: '无已安装的插件',
+      noMCPServersConfigured: '无已配置的 MCP 服务器',
     },
     debugDialog: {
       title: '流水线对话',

web/src/i18n/locales/zh-Hant.ts

@@ -462,6 +462,8 @@ const zhHant = {
       addMCPServer: '新增 MCP 伺服器',
       selectMCPServers: '選擇 MCP 伺服器',
       toolCount: '{{count}} 個工具',
+      noPluginsInstalled: '無已安裝的插件',
+      noMCPServersConfigured: '無已配置的 MCP 伺服器',
     },
     debugDialog: {
       title: '流程線對話',