feat(cli): add verbose logging option for CLI commands

* Introduced a new flag `--verbose` to enable detailed logging.
* Implemented logging for connection events in SSE and stdio commands.
* Added a utility function to handle verbose logging.

internal/observability/http_test.go

@@ -1,10 +1,12 @@
 package observability
 
 import (
+	"bytes"
 	"io"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
 )
@@ -57,3 +59,24 @@ func TestRecoverHandlesPanic(t *testing.T) {
 		t.Fatalf("status = %d, want %d", rec.Code, http.StatusInternalServerError)
 	}
 }
+
+func TestAccessLogUsesForwardedClientIP(t *testing.T) {
+	var buf bytes.Buffer
+	logger := slog.New(slog.NewTextHandler(&buf, nil))
+	handler := AccessLog(logger)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNoContent)
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mcp", nil)
+	req.RemoteAddr = "10.0.0.10:1234"
+	req.Header.Set("X-Real-IP", "203.0.113.7")
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusNoContent {
+		t.Fatalf("status = %d, want %d", rec.Code, http.StatusNoContent)
+	}
+	if !strings.Contains(buf.String(), "remote_addr=203.0.113.7") {
+		t.Fatalf("log output = %q, want remote_addr=203.0.113.7", buf.String())
+	}
+}