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/mcp_server/server.py

@@ -0,0 +1,129 @@
+"""
+MCP Server entry point for viz-platform integration.
+
+Provides Dash Mantine Components validation, charting, layout, theming, and page tools
+to Claude Code via JSON-RPC 2.0 over stdio.
+"""
+import asyncio
+import logging
+import json
+from mcp.server import Server
+from mcp.server.stdio import stdio_server
+from mcp.types import Tool, TextContent
+
+from .config import VizPlatformConfig
+
+# Suppress noisy MCP validation warnings on stderr
+logging.basicConfig(level=logging.INFO)
+logging.getLogger("root").setLevel(logging.ERROR)
+logging.getLogger("mcp").setLevel(logging.ERROR)
+logger = logging.getLogger(__name__)
+
+
+class VizPlatformMCPServer:
+    """MCP Server for visualization platform integration"""
+
+    def __init__(self):
+        self.server = Server("viz-platform-mcp")
+        self.config = None
+        # Tool handlers will be added in subsequent issues
+        # self.dmc_tools = None
+        # self.chart_tools = None
+        # self.layout_tools = None
+        # self.theme_tools = None
+        # self.page_tools = None
+
+    async def initialize(self):
+        """Initialize server and load configuration."""
+        try:
+            config_loader = VizPlatformConfig()
+            self.config = config_loader.load()
+
+            # Log available capabilities
+            caps = []
+            if self.config.get('dmc_available'):
+                caps.append(f"DMC {self.config.get('dmc_version')}")
+            else:
+                caps.append("DMC (not installed)")
+
+            logger.info(f"viz-platform MCP Server initialized with: {', '.join(caps)}")
+
+        except Exception as e:
+            logger.error(f"Failed to initialize: {e}")
+            raise
+
+    def setup_tools(self):
+        """Register all available tools with the MCP server"""
+
+        @self.server.list_tools()
+        async def list_tools() -> list[Tool]:
+            """Return list of available tools"""
+            tools = []
+
+            # DMC validation tools (Issue #172)
+            # - list_components
+            # - get_component_props
+            # - validate_component
+
+            # Chart tools (Issue #173)
+            # - chart_create
+            # - chart_configure_interaction
+
+            # Layout tools (Issue #174)
+            # - layout_create
+            # - layout_add_filter
+            # - layout_set_grid
+
+            # Theme tools (Issue #175)
+            # - theme_create
+            # - theme_extend
+            # - theme_validate
+            # - theme_export_css
+
+            # Page tools (Issue #176)
+            # - page_create
+            # - page_add_navbar
+            # - page_set_auth
+
+            return tools
+
+        @self.server.call_tool()
+        async def call_tool(name: str, arguments: dict) -> list[TextContent]:
+            """Handle tool invocation."""
+            try:
+                # Tool routing will be added as tools are implemented
+                # DMC tools
+                # if name == "list_components":
+                #     result = await self.dmc_tools.list_components(**arguments)
+                # ...
+
+                raise ValueError(f"Unknown tool: {name}")
+
+            except Exception as e:
+                logger.error(f"Tool {name} failed: {e}")
+                return [TextContent(
+                    type="text",
+                    text=json.dumps({"error": str(e)}, indent=2)
+                )]
+
+    async def run(self):
+        """Run the MCP server"""
+        await self.initialize()
+        self.setup_tools()
+
+        async with stdio_server() as (read_stream, write_stream):
+            await self.server.run(
+                read_stream,
+                write_stream,
+                self.server.create_initialization_options()
+            )
+
+
+async def main():
+    """Main entry point"""
+    server = VizPlatformMCPServer()
+    await server.run()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())