feat(landscape): bring experimental ALS therapy landscape to main (#19)

feat(extraction): Batch API extractor (~50% cheaper), fix stale cost banner

feat: retrieval grounding, trial quality, and drug-name typo suggestions

feat: automate ALS seed entities from trials and paper corpus

feat: RRF merge + cross-encoder reranking for retrieval pipeline

perf(extraction): switch to Haiku + add per-paper retry for missed PMIDs

feat: initial project scaffold and Stage 2 ingestion pipeline