feat: map received_quantity_multiplier and sample_rotation (proto drift 24587531)

[HandyS11]

Closes #110.

The ProtoRefresh drift gate flagged two new optional fields on the August 2026 Rust dedicated server (build 24587531). Both are purely additive — no renames or removals — so the wire format stays compatible; they were simply dropped before reaching the public DTOs.

Proto	New field	Surfaced as
AppMarker.SellOrder	optional float received_quantity_multiplier = 11	VendingMachineItem.ReceivedQuantityMultiplier
AppCameraRays	optional Vector3 sample_rotation = 9	CameraFrame.SampleRotation (inherited by CameraRaysEventArg)

Changes

• RustPlusContracts.proto — adopt both fields as reported by the diff.
• VendingMachineItem / CameraFrame — nullable properties following the existing PriceMultiplier / CameraRotation idiom (absent on the wire → null).
• AppMarkerToModel.ToVendingMachineItem — ShouldSerializeReceivedQuantityMultiplier() presence fork.
• AppCameraToModel — mapped in both ToCameraFrame and ToCameraRaysEvent.
• docs/articles/cameras.md — CameraFrame field list kept in sync.

Not changed

CameraRenderer needs nothing: sample placement comes from the fixed 1337-seeded shuffle buffer indexed by SampleOffset, so sample_rotation (the orientation the rays were sampled with) is pass-through data for consumers, not a render input. The golden render fixture is unaffected.

Tests

Written first, watched fail on the missing members, then implemented:

• MarkerMapperTests — set/unset pair for ReceivedQuantityMultiplier.
• CameraModelMapperTests — set/unset for SampleRotation across both mappers.

dotnet test RustPlusApi.sln -f net10.0 → 463 passed. The net8.0 host (netstandard2.0 asset) wasn't runnable locally — that runtime isn't installed on this machine — so CI covers that half; the netstandard2.0 target compiles clean in the full solution build. Coverage on the net10.0 run keeps AppMarkerToModel and AppCameraToModel at 100% line/branch.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Surfaces two newly-added optional protobuf fields from Rust dedicated server build 24587531 into the public DTO layer, keeping the RustPlusApi models/mappers and camera docs aligned with the latest wire contract drift gate.

Changes:

• Add received_quantity_multiplier to AppMarker.SellOrder and map it to VendingMachineItem.ReceivedQuantityMultiplier using a protobuf-net presence fork (ShouldSerialize…() → null when absent).
• Add sample_rotation to AppCameraRays and map it to CameraFrame.SampleRotation (and therefore CameraRaysEventArg) in both camera mappers.
• Extend unit tests and camera documentation to cover/describe the new nullable DTO fields.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/RustPlusApi.UnitTests/MarkerMapperTests.cs	Adds set/unset tests to lock the new sell-order presence fork behavior.
tests/RustPlusApi.UnitTests/CameraModelMapperTests.cs	Adds set/unset tests for SampleRotation across both camera mappers.
src/RustPlusApi/Protobuf/RustPlusContracts.proto	Introduces the two new optional fields matching the reported server drift.
src/RustPlusApi/Extensions/AppMarkerToModel.cs	Maps ReceivedQuantityMultiplier with presence semantics (absent → null).
src/RustPlusApi/Extensions/AppCameraToModel.cs	Maps SampleRotation into both ToCameraFrame and ToCameraRaysEvent.
src/RustPlusApi/Data/VendingMachineItem.cs	Adds nullable DTO property ReceivedQuantityMultiplier with XML doc.
src/RustPlusApi/Data/Cameras/CameraFrame.cs	Adds nullable DTO property SampleRotation with XML doc.
docs/articles/cameras.md	Updates CameraFrame field list to include SampleRotation.