Merge pull request modelcontextprotocol#2770 from kurtisvg/clarify-stdio-server-lifetime

docs(SEP-2575): clarify stdio process lifetime in lifecycle spec

Author: dsp-ant

docs/specification/draft/basic/lifecycle.mdx

@@ -20,11 +20,16 @@ Specifically:
   establish context (e.g., capabilities, protocol version, client identity).
   Every request supplies this metadata in its
   [`_meta`](/specification/draft/basic/index#meta) field.
-- Servers **MUST NOT** require that a client reuse the same connection to
-  perform related operations.
+- Servers **SHOULD** be prepared to handle requests associated with multiple
+  tasks, threads, or conversations. Servers **SHOULD NOT** require that a client
+  reuse the same connection or process to perform related operations. Clients
+  **SHOULD NOT** use an individual task, thread, or conversation as the default
+  lifetime boundary for the stdio process.
 - State that needs to span multiple requests (e.g., long-running tasks,
   application-level handles) **MUST** be referenced by an explicit identifier
   the client passes on each request.
+- Clients **SHOULD** attempt to restart the stdio process if the server
+  terminates unexpectedly.
 
 Long-lived requests like
 [`subscriptions/listen`](/specification/draft/basic/utilities/subscriptions)