fix(tests): resolve Windows CI test failures (#701)

* fix(tests): skip bash tests on Windows and fix USERPROFILE in resolve-ecc-root

- hooks.test.js: add SKIP_BASH guard for 8 bash-dependent tests
  (detect-project.sh, observe.sh) while keeping 207 Node.js tests running
- resolve-ecc-root.test.js: add USERPROFILE to env overrides in 2
  INLINE_RESOLVE tests so os.homedir() resolves correctly on Windows

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Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

* fix(tests): handle BOM in shebang stripping and skip worktree tests on Windows

- validators.test.js: replace regex stripShebang with character-code
  approach that handles UTF-8 BOM before shebang line
- detect-project-worktree.test.js: skip entire file on Windows since
  tests invoke bash scripts directly

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Happy <yesreply@happy.engineering>

tests/ci/validators.test.js

@@ -53,7 +53,13 @@ function writeInstallComponentsManifest(testDir, components) {
 }
 
 function stripShebang(source) {
-  return source.replace(/^#![^\r\n]*(?:\r?\n)?/, '');
+  let s = source;
+  if (s.charCodeAt(0) === 0xFEFF) s = s.slice(1);
+  if (s.startsWith('#!')) {
+    const nl = s.indexOf('\n');
+    s = nl === -1 ? '' : s.slice(nl + 1);
+  }
+  return s;
 }
 
 /**