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_r03.txt

@@ -0,0 +1,43 @@
+  Device: HPCS6500
+  Date: 2026-02-04  Time: 16:50:38
+
+  --- Photometric ---
+  Phi (lm):            0.00
+  eta (lm/W):          0.00
+  CCT (K):                0
+  Duv:              0.00000
+
+  --- Chromaticity ---
+  x:   0.0000    y:  0.0000
+  u:   0.0000    v:  0.0000
+  u':  0.0000    v': 0.0000
+
+  --- CRI ---
+  Ra:  0.0    SDCM: 0.00
+  R1=0, R2=0, R3=0, R4=0, R5=0, R6=0, R7=0, R8=0
+  R9=0, R10=0, R11=0, R12=0, R13=0, R14=0, R15=0
+
+  --- CIE 1931 ---
+  X: 0.000  Y: 0.000  Z: 0.000
+  TLCI-2012: 0
+
+  --- Radiometric ---
+  Phi_e (mW):         0.000
+  Phi_eb (mW):        0.000
+  Phi_ey (mW):        0.000
+  Phi_er (mW):        0.000
+  Phi_efr (mW):       0.000
+
+  --- Electrical ---
+  Voltage (V):         0.00
+  Current (A):       0.0000
+  Power (W):          0.000
+  Frequency (Hz):      0.00
+  Power Factor:      0.0000
+  UThd (%):          0.8692
+  AThd (%):        116.7091
+
+  --- Sensor ---
+  Peak Signal:            0
+  Dark Signal:            0
+  Compensate:             0