Implement rag-search skill for semantic search

Add new skill for semantic search across personal state files and
external documentation using ChromaDB and sentence-transformers.

Components:
- search.py: Main search interface (--index, --top-k flags)
- index_personal.py: Index ~/.claude/state files
- index_docs.py: Index external docs (git repos)
- add_doc_source.py: Manage doc sources
- test_rag.py: Test suite (5/5 passing)

Features:
- Two indexes: personal (116 chunks) and docs (k0s: 846 chunks)
- all-MiniLM-L6-v2 embeddings (384 dimensions)
- ChromaDB persistent storage
- JSON output with ranked results and metadata

Documentation:
- Added to component-registry.json with triggers
- Added /rag command alias
- Updated skills/README.md
- Resolved fc-013 (vector database for agent memory)

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

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

.gitignore

@@ -45,3 +45,7 @@ tmp_unused
 # Todos (managed by Claude Code)
 todos/
 repos/homelab
+
+# RAG search data (generated vector stores and caches)
+data/
+skills/rag-search/venv/