Remove conversions for old saves (t83)

docs/PROJECT_MAP.md

@@ -392,8 +392,8 @@ Dev commands are pure simulation operations; the browser owns the panel and conf
 - functions: resetDevConsole, enableDevConsole, devError, devName, devGiveable, devMaterialList, devDistance, devSuggestions, devHistory, devRemember, devRecall, devComplete, devMaterial, devCommand
 - variables: devWorld, devLog, devFree, devSpeed, devPaused, devSteps, DEV_COMMANDS, DEV_MATERIALS
 
-### src/sim/save.js (216 lines)
-Saving and loading a world (serializeWorld / deserializeWorld) and old-save migration.
+### src/sim/save.js (201 lines)
+Saving and loading a world (serializeWorld / deserializeWorld).
 - functions: serializeWorld, deserializeWorld, startLoadWake, wakeLoadArea, wakeLoadNearBot, loadWakeTick
 - variables: SAVE_VERSION, TOFF
 

docs/agent-log.md

@@ -4,6 +4,16 @@ 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.
 
+## 2026-10-29: t83 remove old-save conversions (Codex)
+
+- Removed only spring, solid-pipe, single-material-filter and foreground-tree conversions
+  from `src/sim/save.js`; world generation and its spring random draws are untouched.
+- Files: save.js, test/t_{load,weather,conveyors}.js, docs/PROJECT_MAP.md, tasks/t83*.
+  Three expectations failed first; updated obsolete spring/filter migration tests deliberately.
+- All 41 headless suites pass; pixel `test/play.py shots/t83-play` passes with no console
+  errors. Sandbox lacked WebGPU; host GPU rerun passed. Inspected saving-progress.png and
+  10-after.png (saved/reloaded world). Map regenerated; nothing left open.
+
 ## 2026-10-29: t81 shared piece direction variants (Codex)
 
 - `pieceV` accepts a direction and resolved code; `dragPlan` calls it for previews and