fix: close the review nits in the write path, query path and tests

Remove the temp file on every writeJSON failure path, not just the write
and close ones. A failed rename left the temp behind with no cleanup.

Surface the list path's unmarshal error instead of printing null with exit
0, and make a non-positive history limit print an empty array rather than
falling through to the whole ring.

Assert the evicted item actually lands in the history ring, so the "files
to history" half of eviction is covered rather than just its signal.

Add the missing README License section beside the GPLv2 text and headers.

2 files changed, 19 insertions, 3 deletions

diff --git a/internal/notify/files.go b/internal/notify/files.go
index 22e0ea9..53e7f3f 100644
--- a/internal/notify/files.go
+++ b/internal/notify/files.go
@@ -54,14 +54,23 @@ func writeJSON(path string, v any) error {
 	if err != nil {
 		return err
 	}
+	tmpName := tmp.Name()
+	renamed := false
+	defer func() {
+		if !renamed {
+			os.Remove(tmpName)
+		}
+	}()
 	if _, err := tmp.Write(data); err != nil {
 		tmp.Close()
-		os.Remove(tmp.Name())
 		return err
 	}
 	if err := tmp.Close(); err != nil {
-		os.Remove(tmp.Name())
 		return err
 	}
-	return os.Rename(tmp.Name(), path)
+	if err := os.Rename(tmpName, path); err != nil {
+		return err
+	}
+	renamed = true
+	return nil
 }
diff --git a/internal/notify/store_test.go b/internal/notify/store_test.go
index 4e4dd79..1fb8bdc 100644
--- a/internal/notify/store_test.go
+++ b/internal/notify/store_test.go
@@ -112,6 +112,13 @@ func TestQueueCapEvictsToHistory(t *testing.T) {
 	if len(*emitted) == 0 {
 		t.Fatal("eviction emitted nothing")
 	}
+	history := s.historySnapshot()
+	if len(history) != 1 {
+		t.Fatalf("history length = %d, want 1", len(history))
+	}
+	if !history[0].Closed {
+		t.Error("evicted entry not marked closed in history")
+	}
 }
 
 func TestHistoryRingCapsAtTwenty(t *testing.T) {