Import: `Frank.GameEngine` 2D scene + `IRenderer2D`

Policies that keep the org coherent

dotnetgovernancenovolis

Status (2026-05-25): Cancelled for Raylib Scene2D import. Platform lane is `Novolis.Rendering.TwoD` + `Novolis.Rendering.Backends.TwoD.Silk`. Optional later: Board<T> only. Master plan: platform-import-plan.md.

Source:

D:\frankrepos\Frank.GameEngine\src\Frank.GameEngine.Primitives — Scene2D, GameObject2D, Camera2D, Sprite2D, Transform2D
D:\frankrepos\Frank.GameEngine\src\Frank.GameEngine.Rendering — IRenderer2D
D:\frankrepos\Frank.GameEngine\src\Frank.GameEngine.Rendering.RayLib — RayLibRenderer2D, 3D overlay/underlay

What

Orthographic 2D scene graph and renderer seam for HUDs, board games, and mini-games — separate from novolis-rendering path tracing.

Why

novolis-rendering is 3D framebuffer / RT focused; no Scene2D.
novolis-raylib has bindings and Game loop but no shared 2D scene model.
Frank samples: Hello2D, Pong, Battleship (Board<T> in Primitives) validate the model.
3D Raylib apps use Underlay2D/Overlay2D for HUD — useful pattern for dogfood.

How

Split import (recommended)

Piece	Target
`Board<T>`, `BoardHistory<T>` (if needed)	`Novolis.Math.Arrays` or `Novolis.Simulation.World` — policy: grid games = Simulation if stateful
`Scene2D`, `GameObject2D`, `Camera2D`	`Novolis.Raylib.Scene2D` (new, references Math for `Vector3` XZ or `Rgba32`)
`IRenderer2D` + Raylib impl	`Novolis.Raylib.Presentation` or `.Game`

Do not

Merge into novolis-math as “2D types” — avoid Vector2; use Vector3 Y=0 per stack policy.
Reference novolis-rendering from Raylib 2D facet.

Port steps

Spike: port Scene2D + RayLibRenderer2D minimal draw (solid quads).
One dogfood sample: Pong or Hello2D using PackageReference only.
Document 3D+2D overlay pattern (Underlay2D) in novolis-raylib/docs.

Priority

P1 after gameengine-assets-mesh-import.md and gameengine-input.md.

Acceptance

Sample runs from NuGet packages only.
No Frank.GameEngine.Rendering.MonoGame unless separate decision (template already exists).