fix(lint): address G114 gosec findings in ready, pprof, and health plugins (#7798)

Replace http.Serve() with http.Server{} configured with timeouts to
address G114 gosec findings (HTTP server without timeouts). This
prevents potential slowloris attacks and resource exhaustion.

Changes:
- Add ReadTimeout, WriteTimeout, IdleTimeout (5s each) to HTTP servers
- Use srv.Shutdown(ctx) for graceful shutdown instead of ln.Close()
- Follow existing pattern from plugin/metrics

Fixes part of #7793

Signed-off-by: Azeez Syed <syedazeez337@gmail.com>

plugin/pprof/pprof.go

@@ -3,10 +3,12 @@
 package pprof
 
 import (
+	"context"
 	"net"
 	"net/http"
 	pp "net/http/pprof"
 	"runtime"
+	"time"
 
 	"github.com/coredns/coredns/plugin/pkg/reuseport"
 )
@@ -15,9 +17,12 @@ type handler struct {
 	addr     string
 	rateBloc int
 	ln       net.Listener
+	srv      *http.Server
 	mux      *http.ServeMux
 }
 
+const shutdownTimeout = 5 * time.Second
+
 func (h *handler) Startup() error {
 	// Reloading the plugin without changing the listening address results
 	// in an error unless we reuse the port because Startup is called for
@@ -42,16 +47,25 @@ func (h *handler) Startup() error {
 
 	runtime.SetBlockProfileRate(h.rateBloc)
 
-	go func() {
-		// #nosec G114 -- TODO
-		http.Serve(h.ln, h.mux)
-	}()
+	h.srv = &http.Server{
+		Handler:      h.mux,
+		ReadTimeout:  5 * time.Second,
+		WriteTimeout: 5 * time.Second,
+		IdleTimeout:  5 * time.Second,
+	}
+
+	go func() { h.srv.Serve(h.ln) }()
 	return nil
 }
 
 func (h *handler) Shutdown() error {
-	if h.ln != nil {
-		return h.ln.Close()
+	if h.srv != nil {
+		ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+		defer cancel()
+		if err := h.srv.Shutdown(ctx); err != nil {
+			log.Infof("Failed to stop pprof http server: %s", err)
+			return err
+		}
 	}
 	return nil
 }