PCB identifiers

Known PCB identifiers:

Module	PCB identifier	Status
Feeder main	BB_Feeder_main_V1	Existing revision
Feeder main	BB_Feeder_main_V1.1	Existing revision
IR light curtain	BB_IR_light_curtain	Existing identifier
Feeder IR barrier	BB_Feeder_IRBarrier_V1.1	To confirm
Raspberry Pi shield	BB_RPi_shield_V1.1	Existing revision
Lighting	BP_Lighting_V1.1	Existing revision

Add schematic links, fabrication packages, and revision notes here as they are finalized.