Rewrite the driver in Rust; move the testbench tools out

The repository is now only the HPCS 6500 driver: a Rust library (serial
transport, every protocol command, block parsing, USBPcap captures, a
simulated instrument) and the hpcs6500 CLI with the flags of the former
hpcs6500.py, plus dump/capture for reverse engineering.

The lamp station, lamp export, TM-30, label printer and LED calibration
move to B4L/lamp-testbench. Golden tests pin the Rust output to the Python
driver's: parsed values bit-exact, report text, CSV and number formatting.
The Python driver is at tag python-final.

tests/golden/format_r01.txt

@@ -0,0 +1,41 @@
+  Device: HPCS6500
+  Date: 2026-02-04  Time: 15:38:14
+
+  --- Photometric ---
+  Phi (lm):          483.74
+  eta (lm/W):         57.40
+  CCT (K):             5635
+  Duv:              0.00561
+
+  --- Chromaticity ---
+  x:   0.3293    y:  0.3494
+  u:   0.2016    v:  0.3208
+  u':  0.2016    v': 0.4813
+
+  --- CRI ---
+  Ra:  82.9    SDCM: 4.84
+  R1=82, R2=94, R3=94, R4=77, R5=81, R6=89, R7=83, R8=64
+  R9=4, R10=84, R11=76, R12=60, R13=86, R14=97, R15=76
+
+  --- CIE 1931 ---
+  X: 667.491  Y: 708.254  Z: 651.135
+  TLCI-2012: 68
+
+  --- Radiometric ---
+  Phi_e (mW):      1501.374
+  Phi_eb (mW):      471.605
+  Phi_ey (mW):      686.214
+  Phi_er (mW):      333.961
+  Phi_efr (mW):      11.231
+
+  --- Electrical ---
+  Voltage (V):       230.29
+  Current (A):       0.0654
+  Power (W):          8.407
+  Frequency (Hz):     50.02
+  Power Factor:      0.5584
+
+  --- Sensor ---
+  Peak Signal:        53279
+  Dark Signal:         2154
+  Compensate:          2834