Replace copy-pasted hasLetter/containsDigit/containsSpace/containsNonLatin
checks across 9 loaders with a single isJunkWord() call. SCOWL and CEDICT
keep their own filtering for valid reasons (SCOWL rejects hyphens/apostrophes,
CEDICT handles non-Latin Chinese characters).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>