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.

Cargo.toml

@@ -0,0 +1,38 @@
+[package]
+name = "hpcs6500"
+version = "0.2.0"
+edition = "2024"
+rust-version = "1.85"
+description = "Open-source driver and CLI for the HPCS 6500 spectrophotometer / integrating sphere"
+repository = "https://git.b4l.co.th/B4L/HPCS6500-py"
+readme = "README.md"
+publish = false
+
+[features]
+default = ["cli"]
+# the `hpcs6500` command line tool; library users can turn it off
+cli = ["dep:clap", "dep:serde_json", "dep:chrono", "dep:ctrlc"]
+
+[lib]
+name = "hpcs6500"
+path = "src/lib.rs"
+
+[[bin]]
+name = "hpcs6500"
+path = "src/cli/main.rs"
+required-features = ["cli"]
+
+[dependencies]
+serialport = "4.7"
+serde = { version = "1", features = ["derive"] }
+thiserror = "2"
+clap = { version = "4.5", features = ["derive"], optional = true }
+serde_json = { version = "1", features = ["preserve_order"], optional = true }
+chrono = { version = "0.4", default-features = false, features = ["clock", "std"], optional = true }
+ctrlc = { version = "3.4", optional = true }
+
+[dev-dependencies]
+serde_json = { version = "1", features = ["preserve_order"] }
+
+[profile.release]
+strip = true