hive-c0re/swarm-*: drop clippy allows and dedupe unix_now + KV open_or_create

No behaviour change. Casts replaced by try_from / Duration math; schedules.rs
reuses agent_renewal::unix_now; the five swarm-queue-client KV open-or-create
copies share one private kv::open_or_create.

swarm-queue-client/src/kv.rs

@@ -0,0 +1,34 @@
+//! The open-or-create sequence every KV bucket module shares.
+
+use crate::Error;
+
+/// Open `bucket`, creating it with `history: 1` and `description` when it
+/// does not exist yet. `label` names the bucket in the creation log line.
+pub(crate) async fn open_or_create(
+    js: &async_nats::jetstream::Context,
+    bucket: &str,
+    label: &str,
+    description: String,
+) -> Result<async_nats::jetstream::kv::Store, Error> {
+    match js.get_key_value(bucket).await {
+        Ok(store) => Ok(store),
+        Err(e) => {
+            tracing::info!(
+                bucket,
+                reason = %e,
+                "{label} bucket not available, creating it"
+            );
+            js.create_key_value(async_nats::jetstream::kv::Config {
+                bucket: bucket.to_owned(),
+                description,
+                history: 1,
+                ..Default::default()
+            })
+            .await
+            .map_err(|source| Error::CreateBucket {
+                bucket: bucket.to_owned(),
+                source,
+            })
+        }
+    }
+}