Drug safety Phase 2: consumer swap

[thefiredev-cloud]

Context

Phase 1 drug safety extraction landed in 480945b (PR #48). Phase 2 swaps in the structured drug safety records as the primary consumer for medication lookups in the app.

Acceptance criteria

• Medication detail screens pull from structured drug_safety table first, chunk fallback second
• Contraindications/interactions rendered from structured fields
• Feature flag drug_safety_v2 toggles provider
• Retrieval eval regression stays green
• Telemetry on structured-vs-chunk hit ratio

Blocker

None. See PR #48 for Phase 1 landing.

Related planning docs

• docs/drug-safety-refactor-plan.md