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_r07.txt

@@ -0,0 +1,41 @@
+  Device: HPCS6500
+  Date: 2026-02-05  Time: 17:57:56
+
+  --- Photometric ---
+  Phi (lm):          182.62
+  eta (lm/W):          0.00
+  CCT (K):             4937
+  Duv:              0.00214
+
+  --- Chromaticity ---
+  x:   0.3474    y:  0.3577
+  u:   0.2106    v:  0.3253
+  u':  0.2106    v': 0.4880
+
+  --- CRI ---
+  Ra:  83.5    SDCM: 1.52
+  R1=82, R2=90, R3=95, R4=82, R5=82, R6=84, R7=87, R8=67
+  R9=13, R10=75, R11=81, R12=54, R13=84, R14=97, R15=76
+
+  --- CIE 1931 ---
+  X: 259.640  Y: 267.378  Z: 220.377
+  TLCI-2012: 71
+
+  --- Radiometric ---
+  Phi_e (mW):       558.636
+  Phi_eb (mW):      152.549
+  Phi_ey (mW):      257.969
+  Phi_er (mW):      144.279
+  Phi_efr (mW):       5.738
+
+  --- Electrical ---
+  Voltage (V):         0.00
+  Current (A):       0.0000
+  Power (W):          0.000
+  Frequency (Hz):      0.00
+  Power Factor:      0.0000
+
+  --- Sensor ---
+  Peak Signal:        55124
+  Dark Signal:         2518
+  Compensate:          2834