Fix theme editor lint warnings

- Remove unused eslint-disable directive in preset swatches
- Add safe eslint-disable for controlled bgKey lookup in ColorField renderer

src/app/admin/theme/page.tsx

@@ -87,6 +87,7 @@ function colorFields(
       {fields.map((f) => {
         const val = toHex(current[f.key], f.def);
         const bgKey = f.bgKey ? `${f.bgKey}${suffix}` : undefined;
+        // eslint-disable-next-line security/detect-object-injection -- bgKey derived from hardcoded field list
         const bgValue = bgKey ? toHex(current[bgKey], "") : undefined;
         return (
           <ColorField
@@ -178,7 +179,6 @@ export default async function AdminTheme({
                         width: 14,
                         height: 14,
                         borderRadius: 3,
-                        // eslint-disable-next-line security/detect-object-injection -- k from hardcoded array
                         background: palette.light[k as keyof typeof palette.light],
                         boxShadow: "inset 0 0 0 1px rgba(0,0,0,0.15)",
                         marginLeft: -3,