Phase 4: play-through checked, final profile, dead code removed, next-step recommendation (t88)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/perf-measure.js

@@ -46,7 +46,6 @@ async function perfRender(lighting, overlays) {
       draw += perfLast.drawWorld / n;
       for (const [key, value] of Object.entries(perfMarks)) marks[key] = (marks[key] || 0) + value / n;
     }
-    const light = 0;
     // Exercise the actual overlay calls and their arguments/conditions in frame().
     PERF_MARKS = false;
     for (let k = 0; k < 5; k++) frame(lastT + 1000 / 60);
@@ -62,7 +61,7 @@ async function perfRender(lighting, overlays) {
       await GPU.timingPromise;
       PERF_MARKS = false; gpu_ms = GPU.gpuMs; marks.gpu = gpu_ms; marks.gpuLight = GPU.lightMs;
     }
-    return { frame_ms, drawWorld_ms: draw, computeLight_ms: light, marks_ms: marks,
+    return { frame_ms, drawWorld_ms: draw, marks_ms: marks,
       overlays: Object.fromEntries(Object.entries(data).map(([key, d]) => [key, { ms_per_frame: d.ms / n, calls: d.calls }])),
       overlay_ms: Object.values(data).reduce((sum, d) => sum + d.ms / n, 0),
       scale: 1, actual_look: SET.look, renderer: 'webgpu', override_cells: GPU.overrideCount || 0, gpu_ms };