Constant SEARCH_RERANK_LIMIT 

pub const SEARCH_RERANK_LIMIT: usize = 10;

0.7.2 PR-2bc S1 fix-1 — production phase-2 rerank LIMIT for engine search. This is the original hardcoded LIMIT 10; it is the default and the floor for search_limit_override (a test seam may RAISE it but never shrink it below this). There is NO env-var override on the hot path.