docs: job-DAG queue model; fold agent_power table into broker.sqlite

coordinator.md rewrites the queue section (node inventory, DAG shapes,
resources, desired-state reconciliation, boot reconcile); approvals.md
+ persistence.md + hivectl --graceful help updated to match. agent_power
lives in broker.sqlite like approvals/questions (own connection + busy
timeout) instead of a separate db file.

hive-c0re/src/job_queue/exec.rs

@@ -130,7 +130,7 @@ async fn run_swap(coord: &Arc<Coordinator>, claim: &Claim, ctx: &Ctx<'_>) -> Res
     let paths = Coordinator::agent_paths(name, agent_dir);
     let result =
         crate::lifecycle::swap_update(name, &hive, &paths, &|step| ctx.step(step), &|log_id| {
-            ctx.build_log(log_id)
+            ctx.build_log(log_id);
         })
         .await;
     match &result {