feat(18-01): implement chi server, auth middleware, overview handler

- Server struct with chi router, embedded template parsing, static file serving
- AuthMiddleware supports Basic and Bearer token with constant-time comparison
- Overview handler renders stats from providers/recon/storage when available
- Nil-safe: works with zero config (shows zeroes, no DB required)
- All 7 tests pass

pkg/web/handlers.go

@@ -0,0 +1,58 @@
+package web
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/salvacybersec/keyhunter/pkg/storage"
+)
+
+// OverviewData holds template data for the overview dashboard page.
+type OverviewData struct {
+	TotalKeys      int
+	TotalProviders int
+	ReconSources   int
+	LastScan       string
+	RecentFindings []storage.Finding
+	PageTitle      string
+}
+
+// handleOverview renders the overview dashboard page with aggregated stats.
+func (s *Server) handleOverview(w http.ResponseWriter, r *http.Request) {
+	data := OverviewData{
+		PageTitle: "Overview",
+	}
+
+	// Provider count.
+	if s.cfg.Providers != nil {
+		data.TotalProviders = s.cfg.Providers.Stats().Total
+	}
+
+	// Recon source count.
+	if s.cfg.ReconEngine != nil {
+		data.ReconSources = len(s.cfg.ReconEngine.List())
+	}
+
+	// Recent findings + total count from DB.
+	if s.cfg.DB != nil && s.cfg.EncKey != nil {
+		recent, err := s.cfg.DB.ListFindingsFiltered(s.cfg.EncKey, storage.Filters{Limit: 10})
+		if err != nil {
+			log.Printf("web: listing recent findings: %v", err)
+		} else {
+			data.RecentFindings = recent
+		}
+
+		// Total count via a broader query.
+		all, err := s.cfg.DB.ListFindingsFiltered(s.cfg.EncKey, storage.Filters{})
+		if err != nil {
+			log.Printf("web: counting findings: %v", err)
+		} else {
+			data.TotalKeys = len(all)
+		}
+	}
+
+	if err := s.tmpl.ExecuteTemplate(w, "layout", data); err != nil {
+		log.Printf("web: rendering overview: %v", err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+	}
+}