build(wasm): standardize asyncify wasm-opt tail to -O1 everywhere

The Binaryen wasm-opt shrink after Asyncify was the only -O2 in the
pipeline: -O2 by default (local + tag release) but -O1 in main CI. The
C++/wx/deps compile is already -O1 everywhere (DEBUG_BUILD defaults to 1;
nothing passes --release in CI/release). Pin the tail to -O1 too:

- apply-asyncify.sh: BINARYEN_OPT_LEVEL default -O2 -> -O1
- release.yml: opt_level -O2 -> -O1 (demo now ships -O1)
- ci-ubicloud.yml / wasm-build.yml / docker/build.sh: refresh stale -O2 comments

Because both callers now build at -O1, the FINAL cache key converges, so a
tag release FINAL-cache-hits main's build and skips the asyncify-tail
rebuild entirely (previously the ~1-2h -O2 wasm-opt was rerun per release).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/ci-ubicloud.yml

@@ -2,10 +2,10 @@ name: CI full build + e2e (Ubicloud)
 
 # Main/PR gate: build all 6 KiCad WASM tools + run the wxWidgets + KiCad e2e
 # suites on a Ubicloud runner. The actual recipe lives in the reusable
-# wasm-build.yml (the SINGLE build definition) — this is just the main/PR caller,
-# pinned to -O1 for fast feedback. The tag release (release.yml) calls the same
-# recipe at -O2 (the shipped demo opt level) and then publishes, so the build can
-# never diverge from what ships.
+# wasm-build.yml (the SINGLE build definition) — this is just the main/PR caller.
+# The asyncify wasm-opt tail is -O1 everywhere (main, release, local); the tag
+# release (release.yml) calls the same recipe at the same -O1 and then publishes,
+# so the build can never diverge from what ships.
 #
 # Routine edits under scripts/ do NOT bust the WASM output cache — only the subset
 # in scripts/deploy/wasm-cache-hash.mjs does. For inputs the sc-hash can't see
@@ -36,8 +36,8 @@ jobs:
   build:
     uses: ./.github/workflows/wasm-build.yml
     with:
-      # -O1: faster asyncify shrink, sufficient for the test gate (the demo ships
-      # -O2 via release.yml). 3D viewer ON so 3d-viewer.spec.ts has a viewer.
+      # -O1 asyncify shrink — the level we ship (release.yml uses the same -O1).
+      # 3D viewer ON so 3d-viewer.spec.ts has a viewer.
       opt_level: "-O1"
       build_3d_viewer: "ON"
       run_tests: true