Integrate FastMCP

This commit integrates FastMCP, a high-level MCP server implementation originally written by Jeremiah Lowin,
into the official MCP SDK. It also updates dependencies and adds new dev dependencies.
It moves the existing SDK into a .lowlevel .

pyproject.toml

@@ -1,7 +1,3 @@
-[build-system]
-requires = ["hatchling"]
-build-backend = "hatchling.build"
-
 [project]
 name = "mcp"
 version = "1.1.2.dev0"
@@ -29,11 +25,31 @@ dependencies = [
     "anyio>=4.5",
     "httpx>=0.27",
     "httpx-sse>=0.4",
-    "pydantic>=2.7.2",
+    "pydantic>=2.7.2,<3.0.0",
     "starlette>=0.27",
     "sse-starlette>=1.6.1",
+    "pydantic-settings>=2.6.1",
 ]
 
+[project.optional-dependencies]
+rich = ["rich>=13.9.4"]
+
+[tool.uv]
+resolution = "lowest-direct"
+dev-dependencies = [
+    "pyright>=1.1.378",
+    "pytest>=8.3.3",
+    "ruff>=0.6.9",
+    "trio>=0.26.2",
+    "pytest-flakefinder>=1.1.0",
+    "pytest-xdist>=3.6.1",
+    "pytest-asyncio>=0.24.0",
+]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
 [project.urls]
 Homepage = "https://modelcontextprotocol.io"
 Repository = "https://github.com/modelcontextprotocol/python-sdk"
@@ -58,15 +74,6 @@ target-version = "py310"
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 
-[tool.uv]
-resolution = "lowest-direct"
-dev-dependencies = [
-    "pyright>=1.1.378",
-    "pytest>=8.3.3",
-    "ruff>=0.6.9",
-    "trio>=0.26.2",
-]
-
 [tool.uv.workspace]
 members = ["examples/servers/*"]