Fix: Accept GGUF files with any version byte

GGUF files can have different version bytes after 'GGUF' (e.g., GGUF\x03 for version 3).
Changed magic byte check from exact match to prefix check.

coderai

@@ -4575,7 +4575,7 @@ def main():
                         with open(model_path, 'rb') as f:
                             magic = f.read(8)
                             print(f"File magic bytes: {magic}")
-                            if magic != b'GGUF':
+                            if not magic.startswith(b'GGUF'):
                                 print(f"ERROR: File is NOT a valid GGUF! Expected 'GGUF', got: {magic}")
                                 print(f"This means the download returned an HTML error page instead of the model.")
                                 print(f"The URL must be a DIRECT download link (ends with .gguf, not a model page)")
@@ -4976,7 +4976,7 @@ def main():
                         with open(model_path, 'rb') as f:
                             magic = f.read(8)
                             print(f"File magic bytes: {magic}")
-                            if magic != b'GGUF':
+                            if not magic.startswith(b'GGUF'):
                                 print(f"ERROR: File is NOT a valid GGUF! Expected 'GGUF', got: {magic}")
                                 print(f"The URL must be a DIRECT download link (ends with .gguf)")
                                 print(f"Image model will load on first request")