Bundle wgpu-native into Linux WebGPU amalgamation (#4220)

.github/scripts/check-linux-webgpu-amalgam

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# Linux-only helper: requires GNU nm long options.
+set -euo pipefail
+
+if [[ $# -ne 1 ]]; then
+  echo "usage: $0 <path-to-libmbgl-core-amalgam.a>" >&2
+  exit 1
+fi
+
+archive_path="$1"
+
+if [[ ! -f "$archive_path" ]]; then
+  echo "archive not found: $archive_path" >&2
+  exit 1
+fi
+
+unresolved_symbols="$(
+  nm -g --undefined-only "$archive_path" \
+    | grep -E '(^|[[:space:]])U[[:space:]]+wgpu([A-Z]|_)' \
+    || true
+)"
+
+if [[ -n "$unresolved_symbols" ]]; then
+  echo "found unresolved WebGPU symbols in $archive_path" >&2
+  echo "$unresolved_symbols" >&2
+  exit 1
+fi
+
+echo "no unresolved WebGPU symbols found in $archive_path"