mcp(feat[foundation]): Add MCP server foundation with FastMCP

why: AI agents need programmatic tmux control via MCP protocol.
what:
- Add fastmcp optional dependency in pyproject.toml
- Add libtmux-mcp entry point script
- Create _utils.py with server caching, object resolvers, serializers,
  and @handle_tool_errors decorator
- Create server.py with FastMCP instance and registration
- Add __init__.py and __main__.py entry points

Author: tony

pyproject.toml

@@ -112,6 +112,14 @@ lint = [
   "mypy",
 ]
 
+[project.optional-dependencies]
+mcp = [
+    "fastmcp>=2.3.0; python_version >= '3.10'",
+]
+
+[project.scripts]
+libtmux-mcp = "libtmux.mcp:main"
+
 [project.entry-points.pytest11]
 libtmux = "libtmux.pytest_plugin"
 

src/libtmux/mcp/__init__.py

@@ -0,0 +1,10 @@
+"""libtmux MCP server - programmatic tmux control for AI agents."""
+
+from __future__ import annotations
+
+
+def main() -> None:
+    """Entry point for the libtmux MCP server."""
+    from libtmux.mcp.server import run_server
+
+    run_server()

src/libtmux/mcp/__main__.py

@@ -0,0 +1,7 @@
+"""Support ``python -m libtmux.mcp``."""
+
+from __future__ import annotations
+
+from libtmux.mcp import main
+
+main()