feat: add @libre.graph.livePhoto facet to driveItem

[dschmidt]

Description

What are Live Photos?

Apple Live Photos are a pair of files: a still image (HEIC or JPEG) and a
short QuickTime video, captured together and linked by a shared content
identifier (a UUID). On the image it is stored in the Apple maker note,
on the video as com.apple.quicktime.content.identifier. Unlike Google
Motion Photos (#36) there is no single embedded file, the two halves are
separate driveItems.

There is no public file format specification; the metadata keys are
documented as AVFoundation metadata identifiers:
https://developer.apple.com/documentation/avfoundation/avmetadataidentifier

What this PR adds

A new read-only @libre.graph.livePhoto facet on driveItem, following the
@libre.graph.motionPhoto pattern. Facet presence means the item was
captured as part of a Live Photo; the counterpart is the driveItem whose
facet carries the same contentId.

Property	Type	Description
contentId	string	UUID shared by both halves, used for pairing.
auto	boolean	Auto Live Photo mode flag (video half only).
vitalityScore	number (float)	0..1 score of how interesting the clip is, used for autoplay decisions (video half only).
vitalityScoringVersion	integer (int64)	Version of the scoring algorithm (video half only).
fullFrameRatePlaybackIntent	integer (int32)	Full frame rate playback intent (video half only).

Example response

{
  "@libre.graph.livePhoto": {
    "contentId": "CD28D161-D5EC-4CDE-8B60-DACCC1363B6B",
    "auto": true,
    "vitalityScore": 0.9398496,
    "vitalityScoringVersion": 4,
    "fullFrameRatePlaybackIntent": 1
  }
}

Validated with openapi-generator-cli v7.13.0 (validate plus a go client
generation smoke test; the generated model and driveItem wiring look as
expected).

Metadata extraction prerequisites on the server side: the video-side keys
are covered by apache/tika#2935, the image-side
Live Photo video index additionally needs
drewnoakes/metadata-extractor#739 (tracked in
https://issues.apache.org/jira/browse/TIKA-4776).

[dschmidt]

Superseded by the same branch pushed to the upstream repo so CI runs there.