build(canvas-wasm): retry past the skia-bindings prebuilt emscripten defect

`BinariesConfig::commit_to_cargo` copies `lib<x>.wasm.a` onto `lib<x>.a` for
every emscripten target, because Skia's wasm GN toolchain emits that suffix
since milestone 148. The published prebuilt archives ship those libraries
already named `lib<x>.a`, so the copy panics on a missing source before
anything is compiled. The library list is derived from the enabled features
rather than from whether ninja ran, so only feature sets pulling in textlayout
or svg are affected — which is exactly this crate's, and exactly the
wasm32-unknown-emscripten combo published for it. Present in every
skia-bindings from 0.97.0 through 0.99.0, so no version choice avoids it.

Seeding the names the build script expects and building again is an identity
operation: it copies each seeded file straight back onto the file it was
copied from, so nothing that gets linked changes. Verified from a clean build
directory — the first attempt panics once, the retry links, and the resulting
module initializes under node with `_init`, `HEAPU8` and `UTF8ToString` all
present, which is what the package's node smoke test asserts.

Forcing a source build instead is not an alternative: Skia m150 wants the
four-argument split-64-bit `glClientWaitSync`, while the pinned emsdk 5.0.0
declares the three-argument `GLuint64` form, and the WebGL interface fails to
compile.

Remove this once commit_to_cargo tolerates an absent `.wasm.a`.

Author: softmarshmallow

crates/grida-canvas-wasm/justfile

@@ -5,6 +5,24 @@
 # Keep this inline (vs. a separate recipe) so the sourced `emsdk_env.sh` affects the same shell.
 _wasm32_unknown_emscripten_env := "rustup target add wasm32-unknown-emscripten; (cd ../.. && ./bin/activate-emsdk); . ../../third_party/externals/emsdk/emsdk_env.sh; command -v emcc >/dev/null 2>&1; export CC=emcc CXX=em++ AR=emar"
 
+# Retry snippet for a skia-bindings defect that makes prebuilt emscripten
+# binaries unusable, so `cargo build` has to be attempted twice.
+#
+# `BinariesConfig::commit_to_cargo` copies `lib<x>.wasm.a` onto `lib<x>.a` for
+# every emscripten target, because Skia's wasm GN toolchain emits that suffix
+# since milestone 148. The published prebuilt archives ship those libraries
+# already named `lib<x>.a`, so the copy panics on a missing source before a
+# single line is compiled. The library list comes from the enabled features,
+# not from whether ninja ran, so this only bites feature sets pulling in
+# textlayout or svg — which is exactly this crate's. Present in every
+# skia-bindings from 0.97.0 through 0.99.0; no version choice avoids it.
+#
+# Seeding the expected names is an identity operation: the build script copies
+# each seeded file straight back onto the file it was copied from, so nothing
+# that gets linked changes. Remove this once commit_to_cargo tolerates an
+# absent `.wasm.a`.
+_seed_emscripten_archives := "for f in ../../target/wasm32-unknown-emscripten/*/build/skia-bindings-*/out/skia/lib*.a; do [ -e \"$f\" ] || continue; [ -e \"${f%.a}.wasm.a\" ] || cp \"$f\" \"${f%.a}.wasm.a\"; done"
+
 # Default recipe - shows available commands
 default:
     @echo "🚀 Grida Canvas WASM Build System"
@@ -88,7 +106,8 @@ _build_wasm32_unknown_emscripten_debug:
     @bash -c 'set -euo pipefail; \
         {{_wasm32_unknown_emscripten_env}}; \
         echo "🧰 $(emcc --version | { IFS= read -r l; echo "$l"; })"; \
-        time cargo build --target wasm32-unknown-emscripten'
+        time { cargo build --target wasm32-unknown-emscripten \
+            || { {{_seed_emscripten_archives}}; cargo build --target wasm32-unknown-emscripten; }; }'
     @echo "✅ Build completed successfully!"
     @echo "📁 Output file: ../../target/wasm32-unknown-emscripten/debug/grida_canvas_wasm.wasm"
     @echo "🎉 Grida Canvas WASM is ready for use!"
@@ -99,7 +118,8 @@ _build_wasm32_unknown_emscripten_release:
     @bash -c 'set -euo pipefail; \
         {{_wasm32_unknown_emscripten_env}}; \
         echo "🧰 $(emcc --version | { IFS= read -r l; echo "$l"; })"; \
-        time cargo build --release --target wasm32-unknown-emscripten'
+        time { cargo build --release --target wasm32-unknown-emscripten \
+            || { {{_seed_emscripten_archives}}; cargo build --release --target wasm32-unknown-emscripten; }; }'
     @echo "✅ Production build completed successfully!"
     @echo "📁 Output file: ../../target/wasm32-unknown-emscripten/release/grida_canvas_wasm.wasm"
     @echo "⚡ Production optimizations applied:"