feat(#2788): carry Skipped to the wire as its own state

A node ruled out by its own dependency edges settles `Skipped` host-side,
but the wire folded it into `Cancelled` and `dag_view` filtered it out
entirely, so a client never saw which branch a run didn't take. Post-#2785
that is not a rare shape: every approval DAG has two not-taken tails and
every rebuild has one, on the happy path as much as on failure.

`State` gains `Skipped`, and it counts as terminal — the wait loops in
hivectl's progress display and the daemon's dag-settled check decide
"finished" with `all(is_terminal)`, so omitting it would hang them on
essentially every DAG.

`dag_view` now emits skipped nodes but no longer lets them keep a DAG
alive. Serialization and completion were the same expression: a DAG left
the snapshot because its nodes had all been filtered away. Keeping skipped
nodes on the wire under that rule would pin every finished deploy in the
queue view forever, so the completion test is now its own flag.

`rollupState` in the dashboard gains the matching arm. It has no `done`
case — `done` is inferred by falling off the wire — so its trailing
`return 'queued'` catches anything it doesn't recognise, and a green
deploy would have read as permanently queued the moment the backend
started emitting the new state. The Rust and JS roll-ups have silently
disagreed before; they are edited together here and say so.

hive-c0re/src/job_queue/tests.rs

@@ -83,8 +83,8 @@ fn settle_rebuild_tail(q: &JobQueue, dag_id: u64, agent: &str, expect_ok: bool)
 }
 
 fn state_of(q: &JobQueue, dag_id: u64) -> State {
-    // A fully-`Done` DAG drops out of the snapshot (its nodes are all
-    // excluded) — absence is the completion signal, so map it to `Done`.
+    // A DAG whose nodes have all settled `Done` or `Skipped` drops out of the
+    // snapshot — absence is the completion signal, so map it to `Done`.
     // Otherwise derive the roll-up from the node set, exactly as every wire
     // consumer does.
     q.snapshot()
@@ -310,6 +310,27 @@ fn non_graceful_rebuild_has_no_signal_or_drain() {
     );
 }
 
+/// A cleanly-finished DAG leaves the snapshot even though its not-taken
+/// failure branch is still in the graph as `Skipped`. Skipped nodes ride the
+/// wire so the dashboard can mark them, which makes "the node list is empty"
+/// and "nothing here is still worth showing" two different questions — only
+/// the second one may drop the DAG. Conflating them pins every completed
+/// deploy in the queue view forever.
+#[test]
+fn settled_dag_leaves_the_snapshot_despite_its_skipped_branch() {
+    let q = JobQueue::new(1);
+    let id = submit(&q, rebuild("agent-a", "r"));
+    for _ in 0..6 {
+        let c = claim_one(&q);
+        q.complete_node(id, c.node_id, Ok(()));
+    }
+    settle_rebuild_tail(&q, id, "agent-a", true);
+    assert!(
+        q.snapshot().iter().all(|d| d.id != id),
+        "a fully settled DAG drops out of the snapshot"
+    );
+}
+
 // ---- build slots ----
 
 #[test]
@@ -858,16 +879,14 @@ fn failed_node_cancels_downstream_but_afterany_reconcile_runs() {
     };
     assert_eq!(by_kind("prebuild"), State::Failed);
     // `StopForUpdate` / `Swap` / `PostSwap` were *ruled out* by the failed
-    // `Prebuild` — `Skipped`, and skipped nodes are filtered off the wire along
-    // with `Done` ones. The failure itself is still visible (the `prebuild` row
-    // above, and the roll-up), which is the part an operator acts on.
-    // Restoring that detail wants a real `Skipped` wire state the client renders
-    // as "not run" — surfacing them as `Cancelled` instead would make a
-    // *successful* DAG with a not-taken branch read as cancelled.
+    // `Prebuild`. They ride the wire as `Skipped` so an operator can see which
+    // steps the run never reached, without them reading as failures of their
+    // own — the roll-up ignores `Skipped` entirely.
     for ruled_out in ["stop_for_update", "swap", "post_swap"] {
-        assert!(
-            dag.nodes.iter().all(|n| n.kind != ruled_out),
-            "{ruled_out} was ruled out, so it is off the wire"
+        assert_eq!(
+            by_kind(ruled_out),
+            State::Skipped,
+            "{ruled_out} was ruled out, so it is on the wire as skipped"
         );
     }
     // The AfterAny reconcile ran (claimed + completed Ok above) → it's `Done`,
@@ -908,9 +927,14 @@ fn swap_failure_still_runs_reconcile() {
     q.complete_node(id, reconcile.node_id, Ok(()));
     let all_dags = q.snapshot();
     let dag = all_dags.iter().find(|d| d.id == id).expect("dag");
-    assert!(
-        dag.nodes.iter().all(|n| n.kind != "post_swap"),
-        "PostSwap is ruled out by the failed Swap (`Skipped`, so off the wire)"
+    assert_eq!(
+        dag.nodes
+            .iter()
+            .find(|n| n.kind == "post_swap")
+            .expect("post_swap node")
+            .state,
+        State::Skipped,
+        "PostSwap is ruled out by the failed Swap, and says so on the wire"
     );
     assert_eq!(
         dag.nodes