outline-budgeter

Merge/simplify an over-fragmented outline to hit a paper-like section budget (NO PROSE): target final ToC ~6–8 H2, fewer thicker H3. **Trigger**: outline budget, merge sections, too many sections, H3 explosion, 大纲预算, 合并小节, 大纲太碎. **Use when**: `outline/outline.yml` exists but would produce thin secti