feat(post-asap): define summary maintenance modes

crates/types/src/post_asap/mod.rs

@@ -32,6 +32,7 @@ pub mod guarantee;
 pub mod query_time;
 pub mod schema;
 pub mod sketch;
+pub mod summary_maintenance;
 
 pub use expr::{SummaryExpr, SummaryNode};
 pub use guarantee::{
@@ -48,3 +49,4 @@ pub use sketch::{
     HydraParams, SamplingKind, SamplingParams, SketchAlgorithm, SketchCategory, SketchKind,
     SketchParams, SketchQuery, StatModelKind, StatModelParams, WaveletKind, WaveletParams,
 };
+pub use summary_maintenance::SummaryMaintenanceMode;

crates/types/src/post_asap/summary_maintenance.rs

@@ -0,0 +1,36 @@
+//! Physical construction mode for a materialized summary.
+//!
+//! A [`super::SummaryNode`] is a logical summary expression and deliberately
+//! does not carry this choice: the same candidate may be built directly for
+//! one workload or maintained incrementally for another. Physical planning
+//! attaches the selected mode to its deployment guarantee.
+
+/// How a physical summary deployment obtains its state.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum SummaryMaintenanceMode {
+    /// Rebuild the summary from its complete input when the deployment needs
+    /// a value. No update stream is required.
+    DirectBuild,
+    /// Create the state once and apply input changes as they arrive.
+    Incremental,
+}
+
+impl SummaryMaintenanceMode {
+    pub const fn as_str(self) -> &'static str {
+        match self {
+            Self::DirectBuild => "direct_build",
+            Self::Incremental => "incremental",
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn maintenance_modes_have_stable_export_names() {
+        assert_eq!(SummaryMaintenanceMode::DirectBuild.as_str(), "direct_build");
+        assert_eq!(SummaryMaintenanceMode::Incremental.as_str(), "incremental");
+    }
+}