- Add _try_rerank() to job_ranker.py: after stack_score sort, rerank
top-50 candidates by (resume_text, description) cross-encoder relevance
- Add resume_text param to rank_jobs(); graceful no-op when empty
- Add reranker gap-reordering pass in rewrite_for_ats(): gaps sorted by
(jd_text, term) relevance before section grouping and LLM rewrite
- Both integrations fall back silently on ImportError or inference failure
- 13 new tests; CF_RERANKER_MOCK=1 for zero-weight test runs
- Closes#108
