refactor(#2897): carry the meta-update inputs on the MetaLock node

Second of the `Dag` field removals, and the same shape as the first:
`DagSpec`/`NodeKind::Dag` carried an `inputs: Vec<String>` that exactly
one node ever read. Both reads live inside `run_meta_lock` — the
`meta::lock_update` call and the `meta_update_cascade_agents` fan-out —
so the list now rides `NodeKind::MetaLock` itself.

The executor stops touching `Claim` for this node entirely: its dispatch
arm already destructured `MetaLock { sweep, fanout }`, so `inputs` joins
them and the `claim` parameter, which had no other use, is gone.

Falls out of that:
- `Claim::inputs` and `DagMeta::inputs` delete.
- `dag_view`'s DAG-level projection onto the `MetaLock` node reads the
  payload instead. The wire `NodeView::inputs` is unchanged: still
  populated on the `meta_lock` node alone.
- the boot sweep names no inputs (it bumps `hyperhive` alone via
  `lock_update_hyperhive`), which the construction site now says out loud
  rather than leaving implicit in an empty DAG-level field.

Checked with clippy (`--all-targets -D warnings`), `cargo test -p
hive-c0re` (320 passed) and `nix fmt`. No option surface is touched, so
no nix-eval gate.

hive-c0re/src/job_queue/model.rs

@@ -84,15 +84,20 @@ pub enum NodeKind {
     /// upstream `Provision` node already registered the agent in meta.
     Create { agent: String },
     /// Meta flake lock bump. `sweep = false`: `meta::lock_update`
-    /// (commit fused, under `META_LOCK`) with the DAG's `inputs`;
+    /// (commit fused, under `META_LOCK`) with this node's own `inputs`;
     /// `sweep = true`: `meta::lock_update_hyperhive`, *non-fatal* (a
     /// failed boot-time bump must not cancel the fan-out rebuilds).
     /// On success the scheduler appends child `Rebuild` DAGs: the
     /// precomputed `fanout` list when present (boot sweep), else the
     /// post-bump affected set (`meta_update_cascade_agents`).
+    ///
+    /// `inputs` are the flake inputs to bump — empty means "all", and the
+    /// boot sweep leaves them empty since it bumps `hyperhive` alone. They
+    /// ride this node because it is the only thing that reads them.
     MetaLock {
         sweep: bool,
         fanout: Option<Vec<String>>,
+        inputs: Vec<String>,
     },
     /// Idempotent power converge *planner*: read `wanted` + observed
     /// state and decide the action (start if `Up` & down, stop if
@@ -281,7 +286,6 @@ pub enum NodeKind {
         source: Source,
         reason: String,
         transient: Option<TransientKind>,
-        inputs: Vec<String>,
         created_at: i64,
     },
 }
@@ -459,8 +463,6 @@ pub struct DagSpec {
     pub source: Source,
     /// Free-form "why".
     pub reason: String,
-    /// Meta-update only: the inputs to bump. Display copy lives on the DAG.
-    pub inputs: Vec<String>,
     /// Dashboard transient pill (and crash-watch suppression) held for
     /// the lease window — from lease acquisition to DAG terminal.
     pub transient: Option<crate::coordinator::TransientKind>,