library_maintenance: log orphan-gc decisions in stale-library path too

run_orphan_gc returned early on the !all_online branch before the
final debug/info log line, so the GC was effectively invisible
whenever any library was Stale — exactly the dry-run scenario where
operators most want to confirm the safety gate is firing. Add the
same conditional log inside the early-return branch (plus a
"deferred — at least one library Stale" hint in the info-level
variant when there's something newly marked).

No behavior change beyond observability.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/library_maintenance.rs

@@ -369,6 +369,19 @@ pub fn run_orphan_gc(
             }
         }
         state.prev_tick_all_online = false;
+        if stats.changed() {
+            info!(
+                "orphan-gc: marked {} new, revived {} (deferred — at least one library Stale; pending: {})",
+                stats.newly_marked,
+                stats.revived,
+                state.pending.len()
+            );
+        } else {
+            debug!(
+                "orphan-gc: stale library, no changes (pending: {})",
+                state.pending.len()
+            );
+        }
         return stats;
     }