Downhill screens no longer shake on screen (t106)

docs/agent-log.md

@@ -4,6 +4,21 @@ 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.
 
+## 2026-10-30: t106 downhill screen frames stay still (Codex)
+
+- Removed the loaded-screen shake flag, pixel/smooth drawing offsets and unused
+  `screenLoaded` helper. No simulation files changed; all src/sim JavaScript hashes match.
+- Replaced the two shake checks with stable-frame equality at ticks 2 and 4; the new check
+  fails before the fix and passes after. Recorded the owner decision; regenerated the map.
+- Files: render/{slope-belts,gpu/smooth-slope}, test/t_slope_belt_art.js,
+  docs/{DESIGN,TESTING,PROJECT_MAP,agent-log}, task t106.
+- All 44 headless suites pass. Before/after raw output differs only in the replaced art checks
+  (saved under /tmp/t106-{before,after}). Build and map check pass.
+- Browser golden fails at GPU.ok; smooth times out waiting for GAME.running. No workaround
+  attempted. Full `run_all.py --browser`: all headless pass, 12 browser suites fail,
+  Firefox smoke passes. Browser diagnostics report webgpu=false and SwiftShader; log at
+  /tmp/t106-browser.log. Screenshots and owner visual check remain. Task in Review; no commit.
+
 ## 2026-10-30: t105 transport matches the t45 belt (Codex)
 
 - Shared diagonal cadence, six-grain vertical slope beds, taller cleat pockets and four-lane