Japanese address normalization (住所正規化): standardize a JP address into clean prefecture / city / town / chome-banchi components. Fixes fullwidth/halfwidth digits, old-form kanji, and chome-banchi notation variants, and resolves the 7-digit postal code. Returns a 0-1 confidence score so agents can flag low-quality input. Use for address validation, cleansing, deduplication, and canonicalization before storage or comparison.