- Removed automatic green flash + cyan color on tag insert
- Callbacks now fully control LED behavior
- Added software_flash() for reliable cross-portal flashing
- Added software_pulse() for breathing effect
- Added apply_effect() unified interface
- Effects run in background threads (non-blocking)
- Tag removal stops any running effects on that pad
- Added legacy_key field to TagInfo for config lookup
- Add per-pad stop event system (_flash_stop_events dictionary)
- Add stop_flash(pad) method to cancel active flash animations
- flash_pad now checks stop events at multiple points in loop
- Tag removal handler calls stop_flash before setting pad to OFF
- Fixes issue where LED flash continued indefinitely after figure removed
