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>

scripts/common/apply-asyncify.sh

@@ -128,9 +128,10 @@ fi
 
 # 3. Post-asyncify shrink. Asyncify spills every live local; without coalescing, large
 # coroutine-entry functions exceed V8's per-function locals limit and stall/crash the renderer.
-# -O1 already runs CoalesceLocals and suffices (CI uses it); -O2 is the default. NOT -Os/-Oz
-# (they break the asyncify runtime — Binaryen #4484). See docs/debugging/DEBUG.md §6-7.
-BINARYEN_OPT_LEVEL="${BINARYEN_OPT_LEVEL:--O2}"
+# -O1 runs CoalesceLocals (enough to keep instrumented functions under V8's local limit) and is the
+# level we ship EVERYWHERE — main CI, tag releases, and local builds all use it. NOT -Os/-Oz (they
+# break the asyncify runtime — Binaryen #4484). See docs/debugging/DEBUG.md §6-7.
+BINARYEN_OPT_LEVEL="${BINARYEN_OPT_LEVEL:--O1}"
 echo "Running wasm-opt ${BINARYEN_OPT_LEVEL} (shrink instrumented functions under V8's local limit)..."
 "${PRELOAD_CMD[@]}" "${TIME_CMD[@]}" "${WASM_OPT}" "${BINARYEN_OPT_LEVEL}" "${FEAT[@]}" ${G} "${OUTPUT_WASM}" -o "${OUTPUT_WASM}"