Add pretty capture.py & log-replay.py, to make i2c reversing extra awesome

[wejn]

I have tweaked the python3/samples/capture.py and added python3/samples/log-replay.py that makes I²C debugging much more pleasant.

Full explanation: https://wejn.org/2026/08/sniffing-i2c-traffic-visually-with-i2cdriver/

A few screenshots, to explain what I mean (with a brief explanation in the title underneath):

better capture using capture.py

shows NACKs properly

replay allows you to viz log.csv the same way (here write with one ACK, one NACK and STOP missing)

For full explanation, the code is it. But anyway -- acked reads/writes are light+bold. Non-acked reads/writes are dimmer and not-bold. If there's non-ack of the address, the heading is red. If there's STOP missing, the ending bracket is red.

I haven't exhaustively tested it, but works for me, and does what I need.

Also note:

• Added possibility to spec speed at cmdline
• Not resetting the bus when starting capture
• When stdout ain't a tty, the colors are skipped