fix: skip aspect_ratio for kling-o1 models and detect image MIME via Pillow

kling-o1-pro and kling-o1-std silently fail when aspect_ratio is included
in the payload — they derive it from the input image. Added
VIDEO_ASPECT_RATIO_MODELS whitelist so only kling-elements and minimax-hailuo
receive the parameter.

Also switched image_to_base64 to use Pillow for format detection instead of
trusting the file extension, which correctly handles files saved with the
wrong extension.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

freepik_cli/utils/files.py

@@ -20,16 +20,24 @@ from rich.progress import (
 
 
 def image_to_base64(path: Path) -> str:
-    """Read an image file and return a base64-encoded string."""
-    suffix = path.suffix.lower().lstrip(".")
-    mime_map = {
-        "jpg": "image/jpeg",
-        "jpeg": "image/jpeg",
-        "png": "image/png",
-        "gif": "image/gif",
-        "webp": "image/webp",
+    """Read an image file and return a base64-encoded string.
+
+    Uses Pillow to detect the actual format rather than trusting the file
+    extension — mismatched extensions (e.g. a JPEG saved as .png) would
+    produce an incorrect MIME type that causes silent failures with some models.
+    """
+    from PIL import Image
+
+    _pillow_to_mime = {
+        "JPEG": "image/jpeg",
+        "PNG":  "image/png",
+        "GIF":  "image/gif",
+        "WEBP": "image/webp",
     }
-    mime = mime_map.get(suffix, "image/jpeg")
+    with Image.open(path) as img:
+        fmt = img.format or "JPEG"
+        mime = _pillow_to_mime.get(fmt, "image/jpeg")
+
     with open(path, "rb") as f:
         encoded = base64.b64encode(f.read()).decode()
     return f"data:{mime};base64,{encoded}"