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

hive-agent/src/harness_state.rs

@@ -87,10 +87,9 @@ fn harness_json_path() -> PathBuf {
 // writer merges into the existing object rather than reconstructing it,
 // so a future second writer preserves fields it doesn't own; the lock
 // closes the lost-update window between a writer's read and its rename.
-// (The forge poller used to be that second writer, for a delivery-dedupe
-// cursor. It no longer persists one — forge's own read-state is the
-// durable record — and it is a separate process now, which an
-// in-process mutex could not have serialised anyway.)
+// (No second writer today — the forge poller that once shared this file
+// now keeps its own delivery-dedupe state and runs as a separate process
+// anyway, which an in-process mutex couldn't have serialised.)
 static HARNESS_JSON_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
 
 /// Read the consolidated state file as a JSON object, or an empty object