Add device path ignore functionality to DetectAll

[wizzomafizzo]

Summary

Adds the ability to specify device paths that should be explicitly ignored during PN532 detection, preventing aggressive probing of sensitive devices.

Changes

• ✅ Add IgnorePaths field to detection.Options struct
• ✅ Implement IsPathIgnored() function with case-insensitive path matching
• ✅ Update UART detector to respect ignore list
• ✅ Update I2C detector to respect ignore list
• ✅ Update SPI detector to respect ignore list
• ✅ Add comprehensive tests covering edge cases
• ✅ Support Unix paths (/dev/ttyUSB0), Windows paths (COM2), and transport-specific formats

Usage Example

opts := detection.DefaultOptions()
opts.IgnorePaths = []string{
    "/dev/ttyUSB0",    // Ignore specific serial port
    "COM2",            // Ignore Windows COM port
    "/dev/i2c-1:0x24", // Ignore I2C device
}

devices, err := detection.DetectAll(&opts)

Key Features

• Early filtering: Paths checked before any communication attempts
• Cross-transport: Works with UART, I2C, and SPI detection
• Case-insensitive: Handles Windows COM port variations
• Path normalization: Resolves relative path components
• Zero overhead: No performance impact for non-ignored devices

Test Coverage

• Empty ignore lists and device paths
• Exact path matching (Unix and Windows)
• Case-insensitive matching
• Multiple path scenarios
• Transport-specific path formats
• Path normalization with relative components
• Edge cases (empty strings, mixed lists)

Fixes the issue where DetectAll could be too aggressive even with existing safety levels.