scenario-unity-shaders

# Unity shaders (technical artist, shading) Expert shading in Unity 6.3 is a shader you can prove: it compiles for the target graphics API, every pass agrees, its variants are counted after stripping, its first use is shown warm, its cost is measured in GPU milliseconds, and its look is checked in a capture with numbers. An agent without a mouse gets there through text: hand-written URP HLSL is the primary route, Shader Graph is used through existing graphs driven by exposed properties plus agent-owned `.hlsl` behind Custom Function nodes, and new graph wiring is a GUI step ([`references/gui-paths.md`](references/gui-paths.md)). Target: 6000.3.21f1, URP 17.3, Shader Graph 17.3, Metal on Apple Silicon. If a sibling skill named here is missing from your available skills, ask the user to install it (`npx skills add scenario-labs/skills --skill <name>`); unattended, proceed from tool schemas and flag the gap. **REQUIRED BACKGROUND:** scenario-unity-expert (channels, review loop, 6.3 traps). Its toolkit (`ut_env`, `ut_run`, `ut_review`, AgentKit) is imported, never copied. **Status (2026-09-24, after the blind-grade refactor):** every procedure ran in Unity 6000.3.21f1 here: `tests/code/unity-shaders/run_all.sh --live` (73 live checks including a development-player PSO proof, 32 offline checks, all passing; evidence in `archive/tests/unity-shaders/`). ## Stance (the expert delta) 1. **Text first, graphs by template.** Shader Graph has no loops and almost no lighting nodes, so...