A loaded world starts around the player first, the rest a few areas a tick (t21)

- Areas within 150 grains of the bot start at once; the others 12 a tick, nearest first, and any
  the bot flies toward start straight away. A Huge world is fully started after 17 s.
- Huge world, first 600 ticks: average 15.2 -> 5.5 ms/tick, worst 79.7 -> 16.2.
- New test/t_load.js.

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

docs/agent-log.md

@@ -4,6 +4,18 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-25: t21: a loaded world starts around the player first (Claude Code, Codex)
+
+- Owner: "lets speed up the first load speed. load in areas around the player first".
+- `src/sim/save.js`: `deserializeWorld` no longer wakes every area; `startLoadWake()` keeps the
+  load-time heat scan's result per area, wakes those within 150 grains of the bot, and queues the
+  rest by distance; `loadWakeTick()` (from `simTick`) wakes 12 a tick and, every 8 ticks, any still
+  waiting within 150 grains of the bot. The queue is not saved.
+- Huge world, ms/tick before -> after: ticks 0-600 average 15.2 -> 5.5, max 79.7 -> 16.2, 95th
+  percentile 21.0 -> 11.0; ticks 600-1800 average 7.3 -> 10.0 (the same work, later). Every area
+  has started by tick 1024 (17 s).
+- `test/t_load.js` (19 checks). `run_all.py --browser` ALL PASSED.
+
 ## 2026-10-24: t21 phase 4: duplicates merged, largest files split (Claude Code, Codex)
 
 - Merged seven real duplicates: wall refunds (`removeWallCell`, walls and molds), tube edges and