fix: re-enable streaming zip on Safari to prevent iOS OOM crash

The buffered zip path (createZipFromUploadFiles) loads all file data into
memory simultaneously: chunks array + Uint8Array copy + JSZip buffer +
output blob = ~3-4x the input size in peak memory. For a 430MB upload,
this reaches ~1.3-1.7GB and triggers iOS Safari's jetsam OOM killer,
causing a silent page refresh with no error.

Re-enable streaming zip for large multi-file uploads on all browsers.
The streaming zip uses constant memory (processes chunks incrementally).
Its size estimates may differ from actual bytes on Safari, but the upload
pipeline handles this gracefully via empty-chunk filtering, the
pre-completion consistency check, and R2 accepting fewer parts than
originally allocated.

Author: heysanil

apps/frontend/src/lib/api.ts

@@ -675,10 +675,12 @@ export async function uploadFiles(
     // Determine upload strategy for multi-file uploads
     const isMultiFile = files.length > 1;
     const totalInputSize = files.reduce((sum, f) => sum + f.size, 0);
-    // On Safari/WebKit, always use buffered zip — streaming zip produces estimated
-    // sizes that can mismatch actual bytes due to HEIC/HEVC lazy transcoding, and
-    // WebKit's ReadableStream can emit empty chunks during transcoding pauses.
-    const useStreamingZip = isMultiFile && totalInputSize >= STREAMING_ZIP_THRESHOLD && !isWebKit;
+    // Streaming zip is used for large multi-file uploads to avoid loading everything
+    // into memory. On Safari, the streaming zip's size estimate may differ from actual
+    // bytes, but the upload pipeline handles this gracefully (fewer/more parts are OK).
+    // The alternative (buffered zip) would OOM-crash iOS Safari for files >200-300MB
+    // since it loads all data + zip output into memory simultaneously.
+    const useStreamingZip = isMultiFile && totalInputSize >= STREAMING_ZIP_THRESHOLD;
 
     // For multiple files, create a zip (buffered for small, streaming for large)
     let uploadBlob: Blob | null = null;
@@ -698,7 +700,7 @@ export async function uploadFiles(
             zipFilename = streamingResult.filename;
             estimatedZipSize = streamingResult.estimatedSize;
         } else {
-            // Small files (or Safari): use buffered zip for exact sizing
+            // Small files: use buffered zip for compression benefits and exact sizing
             const zipResult = await createZipFromUploadFiles(files, onZipProgress);
             uploadBlob = zipResult.blob;
             zipFilename = zipResult.filename;