Initial commit: Nerd Monitor - Cross-platform system monitoring application

Features:
- Multi-platform agents (Linux, macOS, Windows - AMD64 & ARM64)
- Real-time CPU, RAM, and disk usage monitoring
- Responsive web dashboard with live status indicators
- Session-based authentication with secure credentials
- Stale agent detection and removal (6+ months inactive)
- Auto-refresh dashboard (5 second intervals)
- 15-second agent reporting intervals
- Auto-generated agent IDs from hostnames
- In-memory storage (zero database setup)
- Minimal dependencies (Chi router + Templ templating)

Project Structure:
- cmd/: Agent and Server executables
- internal/: API, Auth, Stats, Storage, and UI packages
- views/: Templ templates for dashboard UI
- Makefile: Build automation for all platforms

Ready for deployment with comprehensive documentation:
- README.md: Full project documentation
- QUICKSTART.md: Getting started guide
- AGENTS.md: Development guidelines

internal/ui/handlers.go

@@ -0,0 +1,149 @@
+package ui
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"nerd-monitor/internal/auth"
+	"nerd-monitor/internal/store"
+	"nerd-monitor/views"
+)
+
+// Handler serves UI pages.
+type Handler struct {
+	store *store.Store
+	auth  *auth.Manager
+}
+
+// New creates a new UI handler.
+func New(s *store.Store, a *auth.Manager) *Handler {
+	return &Handler{
+		store: s,
+		auth:  a,
+	}
+}
+
+// Dashboard renders the dashboard page.
+func (h *Handler) Dashboard(w http.ResponseWriter, r *http.Request) {
+	agents := h.store.GetAllAgents()
+	staleAgents := h.getStaleAgents()
+
+	component := views.Dashboard(agents, staleAgents)
+	component.Render(context.Background(), w)
+}
+
+// AgentDetail renders the agent detail page.
+func (h *Handler) AgentDetail(w http.ResponseWriter, r *http.Request) {
+	agentID := r.PathValue("id")
+	agent := h.store.GetAgent(agentID)
+
+	if agent == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	component := views.AgentDetail(agent)
+	component.Render(context.Background(), w)
+}
+
+// Login renders the login page.
+func (h *Handler) Login(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodGet {
+		component := views.LoginPage("")
+		component.Render(context.Background(), w)
+		return
+	}
+
+	if r.Method == http.MethodPost {
+		username := r.FormValue("username")
+		password := r.FormValue("password")
+
+		token, err := h.auth.Login(username, password)
+		if err != nil {
+			component := views.LoginPage("Invalid credentials")
+			component.Render(context.Background(), w)
+			return
+		}
+
+		http.SetCookie(w, &http.Cookie{
+			Name:     "session_token",
+			Value:    token,
+			Path:     "/",
+			MaxAge:   86400,
+			HttpOnly: true,
+			SameSite: http.SameSiteLaxMode,
+		})
+
+		http.Redirect(w, r, "/", http.StatusSeeOther)
+		return
+	}
+
+	http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+}
+
+// Logout handles logout.
+func (h *Handler) Logout(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	cookie, err := r.Cookie("session_token")
+	if err == nil {
+		h.auth.Logout(cookie.Value)
+	}
+
+	http.SetCookie(w, &http.Cookie{
+		Name:     "session_token",
+		Value:    "",
+		Path:     "/",
+		MaxAge:   -1,
+		HttpOnly: true,
+	})
+
+	http.Redirect(w, r, "/login", http.StatusSeeOther)
+}
+
+// RemoveStaleAgents handles bulk removal of stale agents.
+func (h *Handler) RemoveStaleAgents(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	agentIDs := r.Form["agent_ids"]
+	for _, id := range agentIDs {
+		h.store.DeleteAgent(id)
+	}
+
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+// DeleteAgent handles single agent deletion.
+func (h *Handler) DeleteAgent(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	agentID := r.PathValue("id")
+	h.store.DeleteAgent(agentID)
+
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+// getStaleAgents returns agents that haven't reported in 6 months.
+func (h *Handler) getStaleAgents() []*store.AgentStats {
+	const staleThreshold = 6 * 30 * 24 * time.Hour
+	allAgents := h.store.GetAllAgents()
+
+	var stale []*store.AgentStats
+	for _, agent := range allAgents {
+		if time.Since(agent.LastSeen) > staleThreshold {
+			stale = append(stale, agent)
+		}
+	}
+
+	return stale
+}