M5a plan: tasks 21 and 22, from the device check

21: the ledger raises a session's state by the stricter of the grant's
label and the result's own, so a clean session that recalls a
memory-tainted note becomes untrusted and cannot write it into
memory.md (found on straylight, 2026-09-25). 22: the answers to a note
name notes.md, and for an untrusted add the file that was not changed.
The new given tests are ledger_label.rs and new versions of memoryd's
edit.rs and serve.rs; the old copies are kept as -task06 and -task10. On
a scratch tree at the end of task 20: the named tests fail and then pass,
5 and 4 mutations are caught, and the gate passes with 944 tests.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/plans/M5a/files/crates/memoryd/tests/serve.rs

@@ -175,7 +175,7 @@ fn an_untrusted_session_writes_notes_not_identity() {
     ));
     assert_eq!(
         answer,
-        "saved as a note (untrusted): this session has read untrusted content"
+        "not added to memory.md: this session has read untrusted content, so it was saved in notes.md as an untrusted note"
     );
     let memory = std::fs::read_to_string(r.dir.path().join("memory/memory.md")).unwrap();
     assert_eq!(memory, "");
@@ -232,7 +232,7 @@ fn review_holds_identity_writes_but_not_notes() {
         r#"{"action":"note","text":"Not held."}"#,
         false,
     ));
-    assert_eq!(noted, "noted");
+    assert_eq!(noted, "saved in notes.md");
     let (untrusted, _) = content(call(
         &r,
         "mm-b",
@@ -242,7 +242,7 @@ fn review_holds_identity_writes_but_not_notes() {
     ));
     assert_eq!(
         untrusted,
-        "saved as a note (untrusted): this session has read untrusted content"
+        "not added to memory.md: this session has read untrusted content, so it was saved in notes.md as an untrusted note"
     );
     let admin = |command, arg: &str| match ask(
         &r.config.admin_socket(),