fix(ci): resolve cross-platform test failures

- Sanity check script (check-codex-global-state.sh) now falls back to
  grep -E when ripgrep is not available, fixing the codex-hooks sync
  test on all CI platforms. Patterns converted to POSIX ERE for
  portability.
- Unicode safety test accepts both / and \ path separators so the
  executable-file assertion passes on Windows.
- Gacha test sets PYTHONUTF8=1 so Python uses UTF-8 stdout encoding on
  Windows instead of cp1252, preventing UnicodeEncodeError on box-drawing
  characters.
- Quoted-hook-path test skipped on Windows where NTFS disallows
  double-quote characters in filenames.

tests/scripts/check-unicode-safety.test.js

@@ -89,7 +89,7 @@ if (
 
     const result = runCheck(root, ['--write']);
     assert.notStrictEqual(result.status, 0, result.stdout + result.stderr);
-    assert.match(result.stderr, /scripts\/sample\.js:1:23 emoji U\+1F680/);
+    assert.match(result.stderr, /scripts[/\\]sample\.js:1:23 emoji U\+1F680/);
     assert.strictEqual(fs.readFileSync(scriptFile, 'utf8'), original);
   })
 )