feat(viz-platform): create MCP server foundation (#170)

Add viz-platform MCP server structure at mcp-servers/viz-platform/:
- mcp_server/server.py: Main MCP server entry point with async initialization
- mcp_server/config.py: Hybrid config loader with DMC version detection
- mcp_server/dmc_tools.py: Placeholder for DMC validation tools
- pyproject.toml and requirements.txt for dependencies
- tests/ directory structure

Server starts without errors with empty tool list.
Config detects DMC installation status via importlib.metadata.

Closes #170

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

mcp-servers/viz-platform/requirements.txt

@@ -0,0 +1,15 @@
+# MCP SDK
+mcp>=0.9.0
+
+# Visualization
+plotly>=5.18.0
+dash>=2.14.0
+dash-mantine-components>=0.14.0
+
+# Utilities
+python-dotenv>=1.0.0
+pydantic>=2.5.0
+
+# Testing
+pytest>=7.4.3
+pytest-asyncio>=0.23.0