part-specs: VL53L7CX / VL53L7CH obstacle-detection range camera

[OsakaTX]

Summary

Part-specs coverage for the "Obstacle detection range camera" BOM entry (VL53L7CX or VL53L7CH, added upstream in commit d32b27d). Documents both variants, the authoritative CX-vs-CH difference, and the correct LGA-16 pinout.

What this adds

obstacle-detection-tof-vl53l7ch.md:

• Why the BOM lists two variants: VL53L7CX and VL53L7CH are pin-to-pin and driver compatible; the only difference is firmware — the CH additionally exposes Compact Normalized Histogram (CNH) raw per-zone data (up to 128 bins, 37 mm min bin width, 30 Hz) for on-host AI (e.g. floor-type recognition), while the CX outputs standard processed ranging only.
• Common specs (8×8 multizone, 90° FoV, 2-350 cm range, 60 Hz, 940 nm VCSEL, I²C 0x52) with per-line datasheet sourcing.
• Full LGA-16 pinout (A1-C7) with required pull-ups.
• Application guidance for oomwoo (CX default, CH as an AI upgrade path; same footprint).

Source verification

• ST datasheets DS13865 (VL53L7CX Rev 8) and DS14309 (VL53L7CH Rev 3); the CNH-for-AI feature is stated in the VL53L7CH datasheet feature list.
• CX/CH difference confirmed by ST Technical Moderator (Anne BIGOT) on the ST Community.
• Package (LGA-16, 6.4 × 3.0 × 1.6 mm) cross-checked against ST/RS product listings.

Module-level items (breakout PCB mechanicals, cover-glass, bus integration) are marked as open in the gap list. Single-file addition, based on current main.