feat(promql): lower queries to unified operator and scalar IR

Author: zzylol

Cargo.lock

@@ -5,5 +5,6 @@ edition = "2021"
 
 [dependencies]
 asap-types = { path = "../types" }
+asap-frontend-common = { path = "../frontend-common" }
 metricsql_parser = { path = "../metricsql-parser-vendored" }
 thiserror = "2"

crates/frontend-metricsql/Cargo.toml

@@ -324,3 +324,6 @@ fn require_arity(name: &str, actual: usize, expected: usize) -> Result<(), Metri
 fn unsupported(message: impl Into<String>) -> MetricsqlError {
     MetricsqlError::UnsupportedFeature(message.into())
 }
+
+/// Unified lowering, promoted to the root API at planner cutover.
+pub mod unified;