WebGPU renderer complete: dirty uploads, default limits, legacy removed, WebGPU required, warm-up (t88 phase 2d)

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

src/sim/tools.js

@@ -50,7 +50,7 @@ function toolDig(cx, cy, r) {
       if (isWall(b) && !blockIntegrity(((y / BS) | 0) * BW + ((x / BS) | 0))) removeBlock((x / BS) | 0, (y / BS) | 0);
       dug++;
       if ((dug & 3) === 0) emit({ t: 'debris', x, y, m });
-    } else digp[i] = p;
+    } else { digp[i] = p; renderDirtyIdx(i); }
   });
   stats.dug += dug;
   let status = '';