feat: two-stage RRF for fair wiki vs web ranking

- Merge vector+graph into single wiki source before RRF with web
- Wiki pages no longer get 2x advantage from dual retrieval
- Add vector similarity threshold (0.7 default)
- Skip synonyms in graph search to reduce noise
- Fix duplicate entity links bug in graph search

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,29 @@ All notable changes to Library Desk will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.3.0] - 2025-12-15
+
+### Changed
+
+- **Two-Stage RRF Architecture** - Major refactor to level the playing field between wiki and web results
+  - Stage 1: Vector and graph results merged into single "wiki" ranking using mini-RRF
+  - Stage 2: Final RRF between wiki (single source) and web (single source)
+  - Wiki pages no longer get 2x advantage from appearing in both vector and graph searches
+  - Multi-source confirmation still determines wiki internal ranking
+
+- **Skip synonyms in graph search** - LLM-generated synonyms (e.g., "author") no longer match unrelated graph entities (e.g., "author2000")
+  - Vector search still uses synonyms for semantic similarity
+  - Graph search uses only core keywords for exact entity matching
+
+### Added
+
+- `VECTOR_SIMILARITY_THRESHOLD` config setting (default: 0.7) to filter weak vector matches
+- Deduplication in graph search to prevent same document appearing multiple times
+
+### Fixed
+
+- Graph search duplicate entity bug where same document could appear twice if entity linked multiple times
+
 ## [1.2.1] - 2025-12-15
 
 ### Fixed