Initial commit: RAG MCP Server with relationship graph

Features:
- Vector search with Pinecone + Vertex AI embeddings
- Document relationships (link, unlink, related, graph)
- Auto-link with LLM analysis
- Intelligent merge with Gemini

Modular structure:
- clients/: Pinecone, Vertex AI
- tools/: core, relations, stats
- utils/: validation, logging

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

tools/__init__.py

@@ -0,0 +1,16 @@
+"""MCP tools for RAG operations."""
+from .core import rag_save, rag_retrieve, rag_update, rag_delete
+from .relations import rag_link, rag_unlink, rag_related, rag_graph
+from .stats import rag_stats
+
+__all__ = [
+    "rag_save",
+    "rag_retrieve",
+    "rag_update",
+    "rag_delete",
+    "rag_link",
+    "rag_unlink",
+    "rag_related",
+    "rag_graph",
+    "rag_stats"
+]