Iso 2.0 [10/12]: Large Multi-Tile Assemblies (homestead 5×5, cathedral spires)

[putersdcat]

Spec reference

IsoRenderingPlanV2.1.md §5.4 Assemblies; §Addendum D Large Structures

Goal

Pre-defined assembly blueprints place multi-tile structures in the world.
Each assembly is a list of { col, row, kind, variant, zOffset } entries.

Verified assemblies:

• Homestead: 5×4 footprint, homestead-wall perimeter, gate south side, wood-floor interior
• Cathedral: 3×6 nave with cathedral-wall sides, 2-tile spires at north end (zOffset=8)

Technical requirements

• assemblies.ts exports HOMESTEAD_BLUEPRINT, CATHEDRAL_BLUEPRINT as AssemblyEntry[]
• placeAssembly(chunk, blueprint, originCol, originRow) → stamps entries into chunk
• All assembly tiles resolve variants via solver (no hard-coded variant strings in blueprint)
• Cathedral spires: zOffset=8 → 96px tall, visible above surrounding walls

Acceptance criteria (ALL required to close)

• render_nano_scene rendering HOMESTEAD_BLUEPRINT → recognizable house shape, gate on south side, walls meet at corners.
• render_nano_scene rendering CATHEDRAL_BLUEPRINT → nave walls + spires taller than side walls visible.
• No seams or z-fighting between adjacent tiles in either assembly.
• PNGs committed: ProgressEvaluations/assembly-homestead.png, assembly-cathedral.png.
• PNGs show structures from standard iso angle (no debug overlay required, debug optional).