feat(#2591): add NodeKind::Dag DAG-container variant

hive-c0re/src/job_queue/exec.rs

@@ -103,6 +103,10 @@ pub(super) async fn run_node(coord: &Arc<Coordinator>, claim: &Claim) -> Result<
         NodeKind::ResolveApproval => run_resolve_approval(coord, claim).await,
         NodeKind::EmitRebuilt => Ok(run_emit_rebuilt(coord, claim)),
         NodeKind::RevertIntent => run_revert_intent(coord, claim).await,
+        // Pure grouping container — no work; completing it lets it reach
+        // `Finishing` so its child template nodes start. The DAG's terminal
+        // hook fires when the container itself rolls up terminal.
+        NodeKind::Dag { .. } => Ok(NodeOutput::default()),
     }
 }
 

hive-c0re/src/job_queue/model.rs

@@ -14,6 +14,8 @@
 pub use hive_sh4re::jobs::{DagView, NodeId, PermPayload, Source, State, Template};
 use serde::Serialize;
 
+use crate::coordinator::TransientKind;
+
 /// When a dependency edge is considered satisfied.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
 #[serde(rename_all = "snake_case")]
@@ -154,6 +156,24 @@ pub enum NodeKind {
     /// means "don't do it". Noop on any non-cancelled outcome. Appended weak-dep
     /// on the tails; slot/lease-exempt.
     RevertIntent,
+    /// The **DAG container** node: one per submitted DAG, carrying the group's
+    /// domain metadata. Every template node hangs *under* it (its subtree), so
+    /// the container's `NodeId` **is** the DAG id, its rolled-up state **is** the
+    /// DAG state, and it reaching terminal **is** the completion signal that
+    /// fires the DAG's inline hook (approval-resolve / rebuilt-emit /
+    /// intent-revert, dispatched off `template`). Pure grouping — lease- and
+    /// build-slot-exempt; the executor instant-completes it (`Done`) so it
+    /// reaches `Finishing` and its children start.
+    Dag {
+        template: Template,
+        source: Source,
+        reason: String,
+        transient: Option<TransientKind>,
+        approval_id: Option<i64>,
+        inputs: Vec<String>,
+        perm_payload: Option<PermPayload>,
+        created_at: i64,
+    },
 }
 
 impl NodeKind {
@@ -179,6 +199,7 @@ impl NodeKind {
             NodeKind::ResolveApproval => "resolve_approval",
             NodeKind::EmitRebuilt => "emit_rebuilt",
             NodeKind::RevertIntent => "revert_intent",
+            NodeKind::Dag { .. } => "dag",
         }
     }