Rebuild the docs around tested examples; shrink README.v2.md to a pitch (#2978)

docs_src/resources/tutorial002.py

@@ -0,0 +1,15 @@
+from mcp.server import MCPServer
+
+mcp = MCPServer("Bookshop")
+
+
+@mcp.resource("config://app")
+def get_config() -> str:
+    """The active shop configuration."""
+    return "theme=dark\nlanguage=en"
+
+
+@mcp.resource("users://{user_id}/profile")
+def get_user_profile(user_id: str) -> str:
+    """A customer's profile."""
+    return f"User {user_id}: 12 orders since 2021."