[management,client] Normalize anonymize_level and sanity-check the bundle upload URL

Two review follow-ups.

The API validated anonymize_level after trimming and lowercasing but
persisted the value verbatim, so " default " passed as default yet reached
the client — which only lowercases — as an unrecognized value it resolves
to strict. Persist the normalized form so what was validated is what the
client parses.

The remote debug bundle job forwarded the management-supplied upload URL
to the uploader unchecked and logged it at info level, where it can leak a
host, credentials, or query tokens. Reject a malformed or non-https URL
before generating the bundle, and keep the URL out of the info-level line
while leaving the full parameters at debug. The accepted host is left
unrestricted for now, pending a decision on management-directed uploads.

client/internal/engine_bundle_test.go

@@ -0,0 +1,35 @@
+package internal
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestValidateBundleUploadURL covers the sanity check applied to a
+// management-supplied upload URL before a remote debug bundle is generated.
+func TestValidateBundleUploadURL(t *testing.T) {
+	for _, tc := range []struct {
+		name    string
+		raw     string
+		wantErr bool
+	}{
+		{name: "empty falls back to default", raw: ""},
+		{name: "https with host", raw: "https://upload.debug.netbird.io/upload"},
+		{name: "https self-hosted host", raw: "https://upload.example.com"},
+		{name: "plaintext rejected", raw: "http://upload.example.com", wantErr: true},
+		{name: "missing host rejected", raw: "https:///upload", wantErr: true},
+		{name: "non-url scheme rejected", raw: "ftp://upload.example.com", wantErr: true},
+		{name: "garbage rejected", raw: "://not a url", wantErr: true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			err := validateBundleUploadURL(tc.raw)
+			if tc.wantErr {
+				require.Error(t, err, "an invalid upload URL must be rejected")
+				return
+			}
+			assert.NoError(t, err, "a valid or empty upload URL must be accepted")
+		})
+	}
+}