hive-agent: trim narrative comment bloat in doc comments (#3901)

hive-agent/src/events.rs

@@ -99,11 +99,10 @@ pub enum LiveEvent {
     /// Must be a struct variant (not `Note(String)`): internally-tagged
     /// enums can't flatten a tag onto a primitive newtype, and serde
     /// fails serialization at runtime — silently, because the SSE
-    /// handler's `filter_map(... .ok()? ...)` swallows the error. From
-    /// 2025-08 through 2026-05 every `Note` emission was a no-op + the
-    /// sqlite history persisted them as the literal string `"null"`.
-    /// The web UI's `note` renderer already reads `ev.text`, so the
-    /// wire shape matches without a JS change.
+    /// handler's `filter_map(... .ok()? ...)` swallows the error, so a
+    /// regression here goes unnoticed until the sqlite history shows
+    /// `"null"` rows. The web UI's `note` renderer already reads
+    /// `ev.text`, so the wire shape matches without a JS change.
     Note { text: String },
     /// Turn finished. `ok=false` means claude exited non-zero or the
     /// harness hit a transport error.