[Copilot]

Case-insensitive option matching depended on the JVM default locale, which breaks under Turkish locales where ASCII I lowercases to ı. That affected both direct option lookup and abbreviated matching, and could cause variable-arity options to consume what should have been a following named option.

• Root cause

  • Case-insensitive option names were normalized with the default locale in the parser and fuzzy lookup paths.
  • Under tr-TR, --INPUT no longer normalized to the same key as --input.

• Parser changes

  • Centralized lowercase normalization on Locale.ROOT for protocol-style option names.
  • Applied the same normalization consistently in:
    • exact option-name matching
    • prefix matching used by named-option detection
    • abbreviated-option lookup in FuzzyMap

• Regression coverage

  • Added Turkish-locale tests for:
    • --INPUT matching --input when case-sensitive options are disabled
    • abbreviated matching (for example --INP) under the same locale
    • a variable-arity parse where the following option/value pair must not be silently consumed
  • Consolidated locale-mutating tests behind a shared helper so default-locale changes are serialized and restored safely

public static String toLowerCase(String s) {
    return s.toLowerCase(Locale.ROOT);
}