Say what counts as watched in the federation register, not which issue will decide it

src/server/federation.rs

@@ -104,9 +104,16 @@ pub enum SharedItem {
     /// Titles, identifiers, artwork and any metadata that came back about what
     /// is on that server.
     WhatIsInTheLibrary,
-    /// What was played, when, how far it got, and whatever #60 decides counts as
-    /// watched. 0068 places this closest to the sensitive kind, because a
-    /// viewing history says a great deal about a person.
+    /// What was played, when, how far it got, and what counts as watched, which
+    /// is 0060's rule and is applied in [`crate::playback::watched`]. 0068 places
+    /// this closest to the sensitive kind, because a viewing history says a great
+    /// deal about a person.
+    ///
+    /// THIS ITEM SAID "whatever #60 decides counts as watched". That issue
+    /// decided it and closed as completed on 2026-08-27, nine hours after this
+    /// sentence landed, and the module applying the rule arrived two hours after
+    /// that. So the sentence went stale rather than landing refuted, which is the
+    /// milder of the two states. #489 is where it was found.
     WhatWasPlayed,
     /// The queue of actions taken while the server was gone, from #47, which is
     /// the same data with a delay on it.