Update CHANGELOG with VectorDB field fix and error handling improvements

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -29,6 +29,12 @@
 - `ChatMessage` model extended with rag_wiki, rag_vector, mode fields
 
 ### Fixed
+- VectorDB search read wrong field (text vs content) - all results were empty strings
+- VectorDB author/channel are top-level, not nested under metadata
+- Missing API key showed cryptic HTTP 401 instead of helpful guidance
+- Added friendly error messages for HTTP 429/403 during streaming
+
+### Fixed (earlier)
 - "Save failed: fetch().json is not a function" — double await
 - RAG chevron toggle checked CSS class instead of state
 - addMessage wrong arguments (empty objects vs string roles)