fix(web): guard URL strategy import on js_interop, not html (#537)

`dart:html` is only provided by dart2js, so under dart2wasm the
conditional import fell through to the no-op stub and path-based URLs
silently reverted to hash routing — the outcome ADR 0004 rejected.

`dart.library.js_interop` is the supported "compiling for the web"
condition on both dart2js and dart2wasm, so the guard now holds on
either compiler. `kIsWeb` already gates the call itself.

Fixes #525

Author: richardthe3rd

lib/main.dart

@@ -14,8 +14,11 @@ import 'services/services.dart';
 import 'utils/utils.dart';
 import 'widgets/widgets.dart';
 import 'firebase_options.dart';
+// Guarded on dart.library.js_interop, not dart.library.html: `dart:html` is
+// only provided by dart2js, so a `--wasm` build would silently fall through to
+// the no-op stub and revert to hash routing (see ADR 0004, issue #525).
 import 'url_strategy_stub.dart'
-    if (dart.library.html) 'package:flutter_web_plugins/url_strategy.dart';
+    if (dart.library.js_interop) 'package:flutter_web_plugins/url_strategy.dart';
 
 void main() async {
   // coverage:ignore-start