Split Quick Start into Prerequisites (Python/PyUSB/libusb/hardware),
Install (clone + pip), and Running (startup script vs Python module).
Startup script section includes env var override examples.
Added dependency table note — PCAP/GSMTAP/hex dump use only stdlib.
dump.py: tpdu_timestamp_prefix(), tpdu_atr_time_prefix(),
format_message() accepts tpdu_prefix parameter,
FileDumper supports fmt + ATR time tracking
__main__.py: --format/-f flag (hex|timestamp|atr-time),
atr_time_start tracking in message loop
sniff-start.sh: pass through --format/-f and FORMAT env var