v10.24: end-to-end language-aligned goal surface

• refine RULES so candidate goals, advisory /goal, recommendation labels, and recap/closing lines follow the dominant session language end-to-end
• preserve exact literals such as /goal, file paths, version tags, and code identifiers when they should remain exact
• add playground case 16 for end-to-end language-aligned goal-surface behavior while keeping playground non-runtime