camera: macOS uses cgImageRepresentation + ImageIO (skip fileDataRepresentation EXIF)

Per Apple's AVCaptureSession.h docs (line 1106), AVCapturePhotoOutput
applies connection rotation via EXIF tags rather than physical pixel
rotation. The macOS variants of `fileDataRepresentationWithCustomizer`
and `fileDataRepresentationWithReplacementMetadata` are
API_UNAVAILABLE(macos), so we can't replace the embedded EXIF
through the standard customizer.

Workaround: on macOS, grab the raw `AVCapturePhoto.cgImageRepresentation()`
— Apple documents this as "the physical rotation of the CGImageRef
matches that of the main image. Exif orientation has not been
applied." — and re-encode the JPEG via `CGImageDestination` with no
orientation metadata. Resulting JPEG has sensor-native landscape
pixels and no EXIF Orientation tag; viewers and Flutter's image
codec both display as landscape.

iOS path unchanged (still uses fileDataRepresentation).

Diagnostic now fires on both the success and failure branches of
the delegate, so when the capture fails (e.g. the macOS
"OSStatus error 13" the user observed) the failure reason — domain,
code, localized description — is captured to banlu.jsonl instead
of silently dropped.

darwin/Camera/PhotoOutput.swift

@@ -112,9 +112,66 @@ private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegat
         error: Error?
     ) {
         if let error = error as NSError? {
+            diag("photo capture failed: domain=\(error.domain)"
+                 + " code=\(error.code) desc=\(error.localizedDescription)")
             completion(.failure(error))
             return
         }
+
+        let url = URL(fileURLWithPath: NSTemporaryDirectory())
+            .appendingPathComponent("ux_camera_\(UUID().uuidString).jpg")
+
+        #if os(macOS)
+        // Bypass `fileDataRepresentation()` on macOS — it writes EXIF
+        // orientation tags whose semantics differ from iOS and that
+        // we can't reliably override (none of the
+        // `fileDataRepresentationWith…` variants are available on
+        // macOS). Instead grab the raw CGImage — per Apple's docs,
+        // "the physical rotation of the CGImageRef matches that of
+        // the main image. Exif orientation has not been applied." —
+        // and re-encode via ImageIO with no orientation tag at all.
+        // The resulting JPEG carries sensor-native pixel data and
+        // viewers ignore (absent) EXIF, displaying landscape.
+        guard let cgImage = photo.cgImageRepresentation() else {
+            completion(.failure(NSError(
+                domain: "ux.camera",
+                code: -2,
+                userInfo: [NSLocalizedDescriptionKey: "No CGImage data"]
+            )))
+            return
+        }
+        diag("photo: \(cgImage.width)x\(cgImage.height) " +
+             "(cgImageRepresentation, no EXIF)")
+        let destination = CGImageDestinationCreateWithURL(
+            url as CFURL,
+            "public.jpeg" as CFString,
+            1,
+            nil
+        )
+        guard let dest = destination else {
+            completion(.failure(NSError(
+                domain: "ux.camera",
+                code: -3,
+                userInfo: [NSLocalizedDescriptionKey:
+                    "Failed to create JPEG destination"]
+            )))
+            return
+        }
+        let properties: [CFString: Any] = [
+            kCGImageDestinationLossyCompressionQuality: 0.9,
+        ]
+        CGImageDestinationAddImage(dest, cgImage, properties as CFDictionary)
+        if CGImageDestinationFinalize(dest) {
+            completion(.success(url.path))
+        } else {
+            completion(.failure(NSError(
+                domain: "ux.camera",
+                code: -4,
+                userInfo: [NSLocalizedDescriptionKey:
+                    "Failed to finalize JPEG"]
+            )))
+        }
+        #else
         guard let data = photo.fileDataRepresentation() else {
             completion(.failure(NSError(
                 domain: "ux.camera",
@@ -123,29 +180,12 @@ private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegat
             )))
             return
         }
-
-        // Parse the produced JPEG's actual pixel dimensions + EXIF
-        // Orientation so we can see in `banlu.jsonl` whether the
-        // pixel buffer is sensor-native (landscape) or rotated. The
-        // dimensions come from `CGImageSourceCopyProperties` reading
-        // the SOFn marker, EXIF orientation from kCGImagePropertyOrientation.
-        if let src = CGImageSourceCreateWithData(data as CFData, nil),
-           let props = CGImageSourceCopyPropertiesAtIndex(src, 0, nil)
-            as? [CFString: Any] {
-            let w = (props[kCGImagePropertyPixelWidth] as? NSNumber)?.intValue ?? -1
-            let h = (props[kCGImagePropertyPixelHeight] as? NSNumber)?.intValue ?? -1
-            let orient = (props[kCGImagePropertyOrientation] as? NSNumber)?.intValue ?? -1
-            let aspect = w > h ? "landscape" : (h > w ? "portrait" : "square")
-            diag("photo: \(w)x\(h) \(aspect) exifOrientation=\(orient)")
-        }
-
-        let url = URL(fileURLWithPath: NSTemporaryDirectory())
-            .appendingPathComponent("ux_camera_\(UUID().uuidString).jpg")
         do {
             try data.write(to: url, options: .atomic)
             completion(.success(url.path))
         } catch let error as NSError {
             completion(.failure(error))
         }
+        #endif
     }
 }