Optimize terrain rendering for large exports

docs/verification.md

@@ -20,3 +20,9 @@ The real Storage test caught two additional issues that a mock endpoint did not:
 Reports: `artifacts-plugin-regression.json` and `artifacts-api-smoke.json`. Temporary test datasets were deleted and the temporary servers stopped.
 
 This pass did not launch a Minecraft client, use Playwright, or use the Computer plugin. The browser appearance, an actual Fabric capture session, Spigot loading, and a fresh plugin panorama rendering run on macOS still need runtime verification. The existing renderer has not been replaced; earlier renderer proof is recorded separately in `artifacts-renderer-proof.json`.
+
+## Large-export optimization
+
+The subsequent renderer changes replace per-block model transformation and texture loading with cached state templates, numeric section bitsets, bounded typed geometry buffers and spatial meshes. WebP output avoids an intermediate PNG encode, and processed-image uploads run in a four-request pool. GPU selection is automatic with software fallback on initialization failure.
+
+No tests, browsers or benchmarks were run for this change at the user's request. Its speedup and image fidelity on the 2,651,888-block Mac export are unverified. The new per-stage timings, blocks-per-second logs and geometry counts provide measurements for the next real run.