feat: refactor sidebar and settings to include agents and models; update routing and i18n messages

src/i18n/messages.ts

@@ -416,6 +416,8 @@ export const messages: I18nMessages = {
         systemSettings: 'System Settings',
         account: 'Account',
         general: 'General',
+        agents: 'Agents',
+        models: 'Models',
       },
       account: {
         title: 'Account Settings',
@@ -892,6 +894,8 @@ export const messages: I18nMessages = {
         systemSettings: '系统设置',
         account: '账号',
         general: '通用',
+        agents: 'Agents',
+        models: 'Models',
       },
       account: {
         title: '账号设置',
@@ -1368,6 +1372,8 @@ export const messages: I18nMessages = {
         systemSettings: 'システム設定',
         account: 'アカウント',
         general: '一般',
+        agents: 'Agents',
+        models: 'Models',
       },
       account: {
         title: 'アカウント設定',