Cctv Camera Database

New field: night_vision.min_lux (#147 — thanks @fvdpol!). A generic minimum-illumination figure (lux) for datasheets that state a low-light sensitivity without specifying whether the resulting image is colour or black-and-white — complementing min_lux_color (#143), which is specifically the colour threshold. gen-docs and the docs/demo.html viewer render both. Adds a "Minimum Illumination" glossary entry (with the IRE-level caveat on how vendors measure it). (Maintainer follow-up: fixed a missing + in the demo.html table renderer that would have thrown on the Night-vision column.)