calculate_start_timestamp_sql multiplies duration by scrape_interval, making window scrape_interval× too wide #202

// simple_engine.rs:352-355
let scrape_intervals = match_result.query_data[0].time_info.clone().get_duration() as u64;
// scrape_intervals is actually duration in seconds, NOT a count of intervals

end_timestamp - (scrape_intervals * self.prometheus_scrape_interval * 1000)
//               ^ seconds           ^ seconds again → window is interval× too wide

end_timestamp - (scrape_intervals * 1000)

/// With scrape_interval=15s, a 150s SQL temporal query must produce a 150_000ms window.
/// Bug: start = end - (150 * 15 * 1000) = end - 2_250_000ms (15× too wide).
#[test]
fn test_bug_sql_start_timestamp_multiplied_by_scrape_interval() {
    let scrape_interval = 15u64;
    let window_seconds = 150u64;
    let sql_query =
        "SELECT SUM(value) FROM cpu_usage \
         WHERE time BETWEEN DATEADD(s, -150, '2025-10-01 00:00:00') AND '2025-10-01 00:00:00' \
         GROUP BY L1, L2, L3, L4";

    let (_, sql_config, streaming_config) = TestConfigBuilder::new("cpu_usage")
        .with_grouping_labels(vec!["L1", "L2", "L3", "L4"])
        .with_scrape_interval(scrape_interval)
        .add_temporal_query(
            "sum_over_time(cpu_usage[150s])",
            sql_query,
            1,
            window_seconds,
            "tumbling",
        )
        .build_both();

    let sql_engine = SimpleEngine::new(
        Arc::new(NoOpStore),
        sql_config,
        streaming_config,
        scrape_interval,
        QueryLanguage::sql,
    );

    // query_time_sec can be anything; fixed-date SQL query ignores it
    let sql_context = sql_engine
        .build_query_execution_context_sql(sql_query.to_string(), 0.0)
        .expect("Failed to build SQL context");

    let start_ms = sql_context.store_plan.values_query.start_timestamp;
    let end_ms = sql_context.store_plan.values_query.end_timestamp;
    let actual_window_ms = end_ms - start_ms;
    let expected_window_ms = window_seconds * 1000;

    assert_eq!(
        actual_window_ms,
        expected_window_ms,
        "SQL window is {}ms but should be {}ms. \
         Bug: get_duration() (seconds) is multiplied by scrape_interval again.",
        actual_window_ms,
        expected_window_ms
    );
}