design-b D-1 gate: battery green scheduler-only; startModal import scrub + work log

Gate results (single battery, scheduler-only): wx app battery +
asyncify + coroutine 363 passed / 3 skipped / 0 failed; full kicad
suite 138 passed / 30 skipped / 1 failed — the one failure is the
pre-existing local occ-probe glb case (predates D-1, unrelated).

Post-gate scrubs: vestigial 'startModal' removed from ASYNCIFY_IMPORTS
(tests/apps/Makefile.wasm) and env.startModal from
scripts/common/asyncify-imports.txt (the import no longer exists in any
wasm; both lists are boundary supersets so behavior is identical).
Stale comment pointers to the deleted legacy modal machinery updated.
Doc 20: D-1 work log added, status flipped to IN PROGRESS.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TEHGiiXMShNXbBr7gSJ7iz

scripts/common/asyncify-imports.txt

@@ -17,5 +17,4 @@ env.emscripten_idb_*
 # --- Project suspending imports ---
 env.__asyncjs__*
 env.emscripten_fiber_swap
-env.startModal
 env.js_*