0.1.3

Separator migration hotfix.\n\n- Repairs mixed separator boundaries such as S88_-Title, S88-_Title, repeated variants, and suffix equivalents when moving between separators.\n- Suppresses normal tag-to-filename sync during separator migration so follow-up events cannot re-process files with the wrong live separator.\n- Records only successfully renamed files in separator undo data.\n- Allows separator setting changes even when no files need renaming.\n\nValidation: npm test (39/39), npm run build, git diff --check.