feat: terminal sudo blocking, token tracking, mermaid & consumption UI

- Block sudo/doas commands when not running as root
- Add real token counting from API responses
- Track and display consumption by provider/day
- Add Mermaid diagram rendering in Shell and Studio
- Add copy-to-clipboard buttons for code blocks
- Support tables in AI message rendering
- Update system prompt with context (date, time, root status)

💘 Generated with Crush

Assisted-by: MiniMax-M2.7 via Crush <crush@charm.land>

web/src/api/client.js

@@ -38,6 +38,7 @@ const api = {
   importSkill: (path) => request('/skills/import', { method: 'POST', body: JSON.stringify({ import_path: path }) }),
   getDashboardStatus: () => request('/dashboard/status'),
   getProvidersQuota: () => request('/providers/quota'),
+  getProvidersConsumption: () => request('/providers/consumption'),
   getRecentCommands: () => request('/recent-commands'),
   getRunningProcesses: () => request('/running-processes'),
   getSystemMetrics: () => request('/system/metrics'),