refactor: redesign Config as settings window with sidebar panels, remove system overview from Dashboard

- Config: sidebar navigation with 5 panels (Profile, AI Providers, Updates, Locale, Skills)
- Dashboard: remove duplicated system overview section, keep workflows and activity log
- New CSS for config window layout, cards, provider cards, update rows
- Add i18n panel keys (FR/EN)

💾 Generated with Crush

Assisted-by: GLM-5-Turbo via Crush <crush@charm.land>

web/src/api/client.js

@@ -33,6 +33,8 @@ const api = {
   getTerminalSessions: () => request('/terminal/sessions'),
   addSSHConnection: (conn) => request('/terminal/sessions', { method: 'POST', body: JSON.stringify(conn) }),
   deleteSSHConnection: (name) => request(`/terminal/sessions/${encodeURIComponent(name)}`, { method: 'DELETE' }),
+  getChatHistory: () => request('/chat/history'),
+  clearChat: () => request('/chat/clear', { method: 'POST' }),
   sendChat: (message, stream = true) => {
     if (!stream) {
       return request('/chat', { method: 'POST', body: JSON.stringify({ message, stream: false }) })