Vector search + hybrid scoring (rules + embedding similarity)

[highvoltag3]

Query pgvector for top-K relevant stories/approved content. Apply rule-based scoring (e.g., exact tech matches, seniority alignment) to re-rank results.

Acceptance Criteria:
• Vector search returns top-K results.
• Rule boosts applied (e.g., exact tag matches get +score).
• Final ranked list returned to orchestrator.