Surface GCP SDK HTTP wire logs at V(5)

Inject an option.WithLogger slog logger bridged to the zap sink via
logr.ToSlogHandler with a V(1) shift, so the SDK's Debug-level
"api request"/"api response" records (URL, headers, full payloads)
appear only at --zap-log-level=5. Startup warning when active, since
raw insert payloads include cloud-init user-data. Note WithLogger
overrides GOOGLE_SDK_GO_LOGGING_LEVEL for this client.

Co-Authored-By: Claude <noreply@anthropic.com>

internal/provider/gcp/gcp_test.go

@@ -397,6 +397,55 @@ func TestLogging_verbosityTiers(t *testing.T) {
 	}
 }
 
+func TestWireLogger_gatesAtV5(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name      string
+		verbosity int
+		wantDebug bool
+	}{
+		{name: "v5 shows wire records", verbosity: 5, wantDebug: true},
+		{name: "v4 hides wire records", verbosity: 4, wantDebug: false},
+		{name: "v2 hides wire records", verbosity: 2, wantDebug: false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			lines := &[]string{}
+			base := funcr.New(func(prefix, args string) {
+				*lines = append(*lines, prefix+" "+args)
+			}, funcr.Options{Verbosity: tc.verbosity})
+
+			slogger := wireLogger(base)
+			slogger.Debug("api request", "rpcName", "Insert")
+
+			joined := strings.Join(*lines, "\n")
+			if got := strings.Contains(joined, "api request"); got != tc.wantDebug {
+				t.Errorf("Debug record visible = %v, want %v; output:\n%s", got, tc.wantDebug, joined)
+			}
+			if tc.wantDebug && !strings.Contains(joined, "rpcName") {
+				t.Errorf("wire record lost its attrs:\n%s", joined)
+			}
+		})
+	}
+}
+
+func TestWireLogger_infoLandsAtV1(t *testing.T) {
+	t.Parallel()
+	lines := &[]string{}
+	base := funcr.New(func(prefix, args string) {
+		*lines = append(*lines, prefix+" "+args)
+	}, funcr.Options{Verbosity: 1})
+
+	wireLogger(base).Info("hello")
+
+	if joined := strings.Join(*lines, "\n"); !strings.Contains(joined, "hello") {
+		t.Errorf("slog Info should land at V(1) and be visible at verbosity 1; output:\n%s", joined)
+	}
+}
+
 func TestLogging_apiErrorKeepsHTTPDetail(t *testing.T) {
 	t.Parallel()
 	ctx, lines := captureContext(1)