ci(wasm): install wasm-pack via taiki-e prebuilt instead of jetli's stale 0.10

jetli/wasm-pack-action@v0.4.0 with no version: input installs whatever
wasm-pack the action's bundled installer fetches — currently a ~0.10.x
release whose 'build' subcommand does not yet accept --features. Our
build invocation 'wasm-pack build … --features panic-hook' now fails
with

    error: Found argument '--features' which wasn't expected, or isn't
    valid in this context
    USAGE: wasm-pack build --release --target <target>

even though that exact command worked on past runs where the action
happened to install a newer wasm-pack. (The bundler-target release.yml
job passed for v0.2.1 only because it shared the same cached install
on that runner.)

wasm-pack's --features top-level flag has been stable since 0.12.0, so
the fix is to install a fresh wasm-pack each run. Switch both the ci.yml
'WASM build' step and the release.yml 'wasm-publish' job to the same
taiki-e/install-action prebuilt-binary installer we already use for
cargo-llvm-cov and cargo-fuzz. taiki-e tracks the latest wasm-pack
release and the install is a single binary download — no compile, no
shell installer.

The wasm-pack invocations themselves are unchanged.

.github/workflows/release.yml

@@ -370,7 +370,12 @@ jobs:
         with:
           targets: wasm32-unknown-unknown
 
-      - uses: jetli/wasm-pack-action@0d096b08b4e5a7de8c28de67e11e945404e9eefa # v0.4.0
+      - name: Install wasm-pack (latest, via prebuilt binary)
+        # See the matching note in ci.yml: jetli's default installs an old
+        # 0.10.x wasm-pack whose build subcommand rejects --features.
+        uses: taiki-e/install-action@6c1f7cf125e42770ff087ea443901b487cc5471a # v2.79.5
+        with:
+          tool: wasm-pack
 
       - name: Sync root README into bindings/wasm so wasm-pack ships it in pkg/
         # wasm-pack copies the crate's README.md into the generated pkg/