feat(dashboard): single-view grid with live CPU/RAM/Net graphs, API quota, processes, and sudo indicator

- Rewrite dashboard from 4 tabs to single grid view with 5s auto-refresh
- Add live CPU/RAM/Network SVG graphs with rolling 30-point history
- Add backend /api/system/metrics reading /proc/stat, /proc/meminfo, /proc/net/dev
- Add backend /api/providers/quota for MiniMax and Z.AI quota monitoring
- Add backend /api/recent-commands reading bash/zsh history
- Add backend /api/running-processes filtering editors/IDEs/languages
- Add sudo/root indicator (⚡ ROOT) in footer when running as root
- Remove duplicate Ctrl+1-4 shortcut from page-specific footer (keep only right side)
- Add Ctrl+R shortcut on dashboard for metrics-only refresh
- Make API key mandatory in onboarding, auto-scan editors via AI chat
- Remove manual editor input, only show AI-detected editors
- Bump version to 0.3.3

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

internal/api/server.go

@@ -116,6 +116,7 @@ func (s *Server) routes() {
 	s.mux.HandleFunc("/api/providers/quota", s.handleProvidersQuota)
 	s.mux.HandleFunc("/api/recent-commands", s.handleRecentCommands)
 	s.mux.HandleFunc("/api/running-processes", s.handleRunningProcesses)
+	s.mux.HandleFunc("/api/system/metrics", s.handleSystemMetrics)
 }
 
 func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {