Task done: no rgb_fps input, use video's own fps not default

[alfarojdd]

Description

Main changes

Automatic FPS Detection for Videos

• The script now automatically detects the video's native FPS using OpenCV.
• --rgb_fps is now optional for videos (previously required by default).
• --rgb_fps functions as a manual override when specified.
• The FPS source is saved in metadata.json: "fps_source": "auto-detected" or "user-provided".

Supported Input Types

Input	Behavior
Video	Auto-detects FPS (without --rgb_fps), or allows override
Image Directory	Requires --rgb_fps or uses default 30 fps
Single Image	Uses default, fps_source: "default"

Examples of use

# Auto-detect the native FPS of the video (RECOMMENDED)
python spad_emulator.py input.mp4 --output_dir output_spad

# Manual FPS override
python spad_emulator.py input.mp4 --output_dir output_spad --rgb_fps 60

# Directory of images with specified FPS
python spad_emulator.py ./rgb_frames --output_dir output_spad --rgb_fps 60

Secundary changes

Automatic code reformatting with Ruff (Python formatter/linter)

• Improved indentation and spacing
• Very long lines broken
• Organized imports
• Cleaner, more readable code