(new): expand runtime APIs

(fix): harden concurrent lifecycle
(tests): add regression coverage
(doc): update v1.2 guidance

utils/limiter_test.go

@@ -189,3 +189,18 @@ func TestRateLimiterCleanupEvictsIdleChats(t *testing.T) {
 		t.Fatal("expected future chat 11 lock to remain")
 	}
 }
+
+func TestRateLimiterCleanupPreservesAcquiredLimiter(t *testing.T) {
+	rl := NewRateLimiter()
+	limiter, release := rl.acquireChatLimiter(42)
+
+	rl.chatMu.Lock()
+	rl.chatLastSeen[42] = time.Now().Add(-time.Hour)
+	rl.chatMu.Unlock()
+	rl.Cleanup(time.Minute)
+
+	if got := rl.getChatLimiter(42); got != limiter {
+		t.Fatal("Cleanup replaced a limiter while it was acquired")
+	}
+	release()
+}