Moppe repository orientation (synced code)

The Moppe code repository is synced into Sheaf as source files under document 3CV92Z. Orientation: Moppe is a C++ motorcycle game / generated-world laboratory. Key entry points: docs/engine-atlas.md (architecture map: WorldRecipe+TerrainProgram → GeneratedWorld → GameSession → FrameView → Renderer, Metal + WebGPU backends), docs/project.org (experiment ledger with acceptance evidence and working rules), docs/terrain-expressions.md (scalar-field DAG terrain language), ideas/ (second-author, tending-the-world, watersheds-of-execution, reading-map essays).

Direct corpus links: the AnalyticalErosion transform implements the finite-time n=1 characteristic solution from Tzathas et al. #DWXKYQ standing water uses Priority-Flood #MTDKDE FastFlow #NV2YRW is named as a possible GPU routing backend; TrailFormation as a terrain transform connects to the active-walker trail papers #B6P8L4 #GY93FG the ideas/ essays on centers, routes, and settlements connect to the Alexander / living-structure folder. ideas/reading-map.md is the annotated ancestor of the Sheaf literature corpus.

Current active work per the ledger: river rendering as continuous cubic alignments (ribbons), waterfall geometry, junction meshes, erosion coupled to lake infill, and making the random world a legible ride.