Perf pass: the frame, one area at a time

Loop: survey → rank → pass → write back, one area per pass, until the frame fits the budgets at every play position. The model-pass skill works on one object; this one works on the frame: what the play camera actually draws, in every pass, from where the player actually stands. Every number is measured in the running app, never estimated; every "looks the same" is a pixel diff and a look at the shots.

Words used below:

• Frame: one rendered frame as the draw ledger records it (three-audit's ledger()): every draw call by object and pass, with its triangles. The scene's totals (tris(), census(), summary()) are the world's worth, culled or not; they explain a cost, the ledger measures it.
• Play position: a place in play the player sees the scene from: the app's own camera at a height, moment, level or screen. The frame changes with each; a pass is judged at all of them.
• Area: one ledger group or scene part that costs as one thing (the city, the forest, the wires, the shadow pass). One area per pass.
• Budgets: the project's defineBudgets file (src/budgets.ts): frame is the target, parts the ceilings tests hold.
• Style guide: the project's 3D-STYLE.md, as the model-pass skill keeps it. Its Budgets say why, its Pass log records every pass.
• Studio: the project's @zkmake/three-studio page; a pass gives its area a mode and views there.
• Baseline table: the survey's numbers, one row per play position, kept for the whole loop.

The tools are the @zkmake/* packages. This skill names their calls; the installed package's README (node_modules/@zkmake/<name>/README.md, or https://zkmake.github.io/three-kit/llms-full.txt) is the authority on their signatures. Paths below are relative to this skill's directory.

0. Style guide, budgets, helpers