fix: resolve 7 bugs from QA sweep (#208)

- Fix selective metadata stripping (P1): use Sharp's keepExif()/keepIccProfile()
  instead of broken withMetadata({}) that preserved everything
- Fix meme font mapping (P1): add ArchivoBlack and ComicNeue fonts, map
  arial-black and comic-sans to correct TTF files instead of Anton
- Fix meme contentType (P2): detect actual output format from Sharp metadata
  instead of hardcoding image/png
- Fix info/text-overlay/color-palette i18n (P2): wire up existing translation
  keys that were imported but never used
- Fix info and color-palette displayMode (P2): change from before-after to
  no-comparison since neither tool produces a processed image
- Add missing i18n keys across all 21 locales
- Update displayMode test assertions

packages/image-engine/src/operations/strip-metadata.ts

@@ -6,7 +6,6 @@ export async function stripMetadata(
 ): Promise<Sharp> {
   const { stripExif, stripGps, stripIcc, stripXmp, stripAll } = options;
 
-  // Default behavior: strip all metadata
   const shouldStripAll =
     stripAll === true ||
     (stripExif === undefined &&
@@ -16,23 +15,28 @@ export async function stripMetadata(
       stripAll === undefined);
 
   if (shouldStripAll) {
-    // withMetadata({}) with no options strips everything;
-    // but to truly strip we avoid calling withMetadata at all.
-    // Sharp strips metadata by default when outputting.
-    // Calling .withMetadata() KEEPS metadata, so we do NOT call it.
     return image;
   }
 
-  // Selective stripping: we keep metadata but remove specific fields.
-  // Sharp's withMetadata lets us keep ICC, EXIF, etc.
-  // We call withMetadata to keep what wasn't requested stripped.
-  const keepIcc = !stripIcc;
+  const strippingNothing = !stripExif && !stripGps && !stripIcc && !stripXmp;
+  if (strippingNothing) {
+    return image.withMetadata();
+  }
 
-  return image.withMetadata({
-    // If we want to keep ICC, pass undefined (Sharp default keeps it with withMetadata)
-    // If we want to strip ICC, we need to not call withMetadata at all or handle differently
-    // Sharp's withMetadata keeps metadata; without it, metadata is stripped.
-    // For selective stripping, we strip all first then re-add what we want to keep.
-    ...(keepIcc ? {} : {}),
-  });
+  // Selective stripping: Sharp strips all metadata by default (no calls needed).
+  // We chain keepExif() / keepIccProfile() to preserve categories the user
+  // does NOT want stripped.
+  let pipeline = image;
+
+  if (!stripExif && !stripGps) {
+    pipeline = pipeline.keepExif();
+  }
+
+  if (!stripIcc) {
+    pipeline = pipeline.keepIccProfile();
+  }
+
+  // XMP: Sharp has no keepXmp() method. XMP is always stripped in selective mode.
+
+  return pipeline;
 }