fix(webgal): map global to globalThis in browser builds

[modenicheng]

Summary

Map the browser bundle's global identifier to globalThis so expression evaluation works in browser builds.

Problem

angular-expressions@1.4.3 accesses Node's global during compile():

if (global.storeFnString) {
  global.storeFnString(fnString);
}

When WebGAL runs in a browser bundle, global is undefined. This makes expression evaluation fail with:

ReferenceError: global is not defined

The failure affects script expressions such as setVar:morale=morale+1 and conditional evaluation used by -when. In the current error handling, those failures can silently turn into an empty variable value or a false condition.

Fix

Configure Vite to replace global with the browser-standard globalThis in the generated bundle. This keeps the fix scoped to the browser build and avoids changing WebGAL's expression semantics.

Validation

• git diff --check passes.
• The project's existing PR workflow will run parser tests and the full WebGAL build.

This is separate from #1005, which addresses expression evaluation semantics and variable extraction rather than the browser global compatibility failure.