Cleanup: Remove remaining ChromaDB references from documentation and comments

[manana2520]

Summary

After the migration to Graphiti as the sole storage layer, there are still 58 references to ChromaDB in comments, docstrings, and deprecated function names across 17 files.

Background

ChromaDB has been eliminated from the codebase (see recent commits). Graphiti (with Kuzu for dev, Neo4j for prod) is now the single source of truth for all knowledge data. However, documentation and comments still reference the old architecture.

Files to Update

src/knowledge_base/lifecycle/feedback.py (2 references)
src/knowledge_base/lifecycle/quality.py (2 references)
src/knowledge_base/slack/admin_escalation.py (1 reference)
src/knowledge_base/slack/ingest_doc.py (6 references)
src/knowledge_base/db/database.py (1 reference)
src/knowledge_base/cli.py (3 references)
src/knowledge_base/search/hybrid.py (1 reference)
src/knowledge_base/search/models.py (1 reference)
src/knowledge_base/db/duckdb_schema.py (1 reference)
src/knowledge_base/db/models.py (13 references)
src/knowledge_base/chunking/parser.py (4 references)
src/knowledge_base/config.py (2 references)
src/knowledge_base/confluence/downloader.py (12 references)
src/knowledge_base/db/__init__.py (2 references)
src/knowledge_base/graph/graphiti_retriever.py (3 references)
src/knowledge_base/graph/entity_schemas.py (1 reference)
src/knowledge_base/graph/graphiti_builder.py (3 references)

Tasks

• Update docstrings to reference Graphiti instead of ChromaDB
• Update comments mentioning "ChromaDB source of truth" to "Graphiti source of truth"
• Consider renaming deprecated functions (e.g., apply_feedback_to_quality_chromadb → apply_feedback_to_quality_graphiti)
• Update ADR references (e.g., docs/adr/0005-chromadb-source-of-truth.md)
• Update db/models.py deprecated model documentation
• Clean up plan/ directory documentation files

Notes

• This is a low-priority cleanup task - the code works correctly with Graphiti
• No runtime behavior changes needed
• Consider doing this incrementally during regular maintenance

Related

• Graphiti migration completed in recent commits
• All 326 unit tests pass
• E2E tests pass (16 passed, 78 skipped for missing Slack credentials)