refactor(go): drop unused realtime geo index

go/vehicle-gateway/internal/realtime/snapshot_writer.go

@@ -371,8 +371,7 @@ const realtimeLocationTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_realtime_lo
   updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
   PRIMARY KEY (protocol, vin),
   KEY idx_vin (vin),
-  KEY idx_protocol_updated (protocol, updated_at),
-  KEY idx_location (longitude, latitude)
+  KEY idx_protocol_updated (protocol, updated_at)
 )`
 
 const upsertRealtimeLocationSQL = `

go/vehicle-gateway/internal/realtime/snapshot_writer_test.go

@@ -62,6 +62,9 @@ func TestSnapshotWriterEnsuresSchemaAndUpsertsCoreSnapshot(t *testing.T) {
 			t.Fatalf("realtime current-state table should key by protocol/vin: %s", call.query)
 		}
 	}
+	if strings.Contains(exec.calls[1].query, "idx_location") {
+		t.Fatalf("realtime location table should not keep unused geo index: %s", exec.calls[1].query)
+	}
 	upsert := exec.calls[2]
 	if !strings.Contains(upsert.query, "ON DUPLICATE KEY UPDATE") {
 		t.Fatalf("upsert query = %s", upsert.query)