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>

utils/__init__.py

@@ -0,0 +1,11 @@
+"""Utility modules for RAG system."""
+from .validation import validate_content, validate_tag, validate_document_id
+from .logging import setup_logging, get_logger
+
+__all__ = [
+    "validate_content",
+    "validate_tag",
+    "validate_document_id",
+    "setup_logging",
+    "get_logger"
+]