chore: import upstream snapshot with attribution

examples/stories/lifespan/server.py

@@ -0,0 +1,39 @@
+"""Process-scoped dependency injection via `MCPServer(lifespan=...)`."""
+
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
+from dataclasses import dataclass
+from typing import Any
+
+from mcp.server.mcpserver import Context, MCPServer
+from stories._hosting import run_server_from_args
+
+
+@dataclass
+class AppState:
+    db: dict[str, str]
+
+
+@asynccontextmanager
+async def app_lifespan(server: MCPServer[AppState]) -> AsyncIterator[AppState]:
+    """Acquire process-scoped resources at startup; release them at shutdown."""
+    db = {"alpha": "one", "beta": "two"}  # e.g. `await pool.connect()`
+    try:
+        yield AppState(db=db)
+    finally:
+        db.clear()  # e.g. `await pool.disconnect()`
+
+
+def build_server() -> MCPServer[AppState]:
+    mcp = MCPServer[AppState]("lifespan-example", lifespan=app_lifespan)
+
+    @mcp.tool(description="Look up a key in the process-scoped store.")
+    def lookup(key: str, ctx: Context[AppState, Any]) -> str:
+        # Interim 3-hop path; shortens to `ctx.state.db` in a later release.
+        return ctx.request_context.lifespan_context.db[key]
+
+    return mcp
+
+
+if __name__ == "__main__":
+    run_server_from_args(build_server)