fix(types): add root types.d.ts shim for node10 module resolution

attw fails under node10 resolution because it ignores the "exports" map and
the types module has no root shim. Create a declaration-only root shim
(types.d.ts without a runtime types.js) in postbuild, matching how the other
modules are exposed to node10 consumers.

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

Author: dayongkr

.scripts/postbuild.sh

@@ -49,6 +49,10 @@ if [ -d dist/types ]; then
     find dist/types -type f \( -name '*.js' -o -name '*.mjs' -o -name '*.cjs' \) -delete
 fi
 
+# node10 moduleResolution ignores "exports", so it needs a root shim like the other
+# modules. Declaration-only, so only the .d.ts is created (no types.js counterpart).
+echo "export * from './dist/types';" > types.d.ts
+
 # Create compat directory
 mkdir -p compat