feat: add phase-1 retrieval ranking and release 0.1.4

[tryweb]

Summary

• add phase-1 retrieval ranking in memory search with RRF fusion, recency boost, and importance weighting, including new retrieval config/env controls
• add deterministic foundation/regression coverage for ranking behavior and config defaults/overrides, and update docs/specs for low-feedback evaluation guidance
• bump package version to 0.1.4 with changelog updates and archive the completed OpenSpec ranking change

Verification

• docker compose build --no-cache && docker compose up -d
• docker compose exec app npm run verify