Function report_upstream_error 

pub fn report_upstream_error(
    provider: &str,
    operation_id: &str,
    upstream_status: u16,
    proxy_status: u16,
    error_type: Option<&str>,
    error_message: Option<&str>,
)

Attach structured tags + fingerprint to the current Sentry scope and emit a tracing event at the appropriate level for the given upstream status class.

Levels: 402 / 403 / 422 → warn (expected client-side upstream error, Sentry event at warning level for filtering, does not page) all others → error (includes 5xx, network failures, unknown)

When the sentry feature is off, emits the tracing event only.