Add AS7331 UV spectral sensor component definition

Companion to adafruit/Adafruit_Wippersnapper_Arduino#892.
AS7331 is a triple-channel UV sensor (UVA/UVB/UVC) by ams-OSRAM,
exposing UVB as a raw subcomponent. I2C addresses 0x74-0x77.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tyeth

components/i2c/as7331/definition.json

@@ -0,0 +1,9 @@
+{
+  "displayName": "AS7331",
+  "vendor": "ams-OSRAM",
+  "productURL": "https://www.adafruit.com/product/6476",
+  "documentationURL": "https://github.com/adafruit/Adafruit_AS7331",
+  "published": false,
+  "i2cAddresses": ["0x74", "0x75", "0x76", "0x77"],
+  "subcomponents": [{ "displayName": "UVB", "sensorType": "raw" }]
+}