wip(#3001): convert remaining unblocked call sites; sweep docs

21 of 28 non-test call sites now insert directly. power.rs compiles.
The only remaining errors are server.rs's 5, which are blocked: those
sites feed the returned id into HostResponse::queued -> `queued_dags`,
a wire field hivectl polls via QueueDag. Removing the container without
answering that breaks hivectl's wait/progress loop; asked on the issue.

Also swept the deleted symbol out of prose, not just code:
- docs/coordinator.md: "the submit layer (job_queue/submit.rs)" ->
  the power layer (job_queue/power.rs), and "submits" -> "inserts".
- templates.rs module doc: points at super::power for the power ops.
- lifecycle_ops.rs module doc: says which path each op takes now.
- mod.rs's insert_group comment restated the open issue verbatim
  ("a DAG is addressed by its container node, which submit inserts
  itself"). Replaced with what is actually true for that path.

Dashboard behaviour deltas worth review: insert failures are now
logged per agent instead of swallowed, and UPDATE-ALL emits one queue
snapshot after the loop rather than one per agent.

hive-c0re/src/job_queue/mod.rs

@@ -161,9 +161,9 @@ fn insert_group(
     inner
         .insert_job(group_parent, |b| {
             declare(b);
-            // c0re names no handles: a DAG is addressed by its container node,
-            // which `submit` inserts itself, and nothing downstream looks an
-            // individual step up by id.
+            // A runtime-appended subgraph is addressed by the node that emitted
+            // it (`group_parent`), so this path names nothing. Callers that DO
+            // want a handle use `JobQueue::insert` and name the node there.
             Vec::new()
         })
         .map_err(|e| anyhow::anyhow!("job_queue: graph insert failed: {e}"))?;

hive-c0re/src/job_queue/power.rs

@@ -16,8 +16,9 @@ use std::sync::Arc;
 
 use hive_jobq::NodeId;
 
-use super::JobBuilder;
-use super::templates;
+use super::resource::Resource;
+use super::templates::rebuild_nodes;
+use super::{JobBuilder, NodeKind};
 use crate::coordinator::Coordinator;
 use crate::lifecycle;
 

hive-c0re/src/job_queue/templates.rs

@@ -17,8 +17,8 @@
 //!
 //! The hive-wide **power ops** (`stop` / `start` / `restart`) are NOT here:
 //! their per-agent shape depends on live running state (an async
-//! `lifecycle::is_running` read), so `submit.rs` assembles them out of the
-//! primitives this module exports ([`rebuild_nodes`]).
+//! `lifecycle::is_running` read), so [`super::power`] assembles them out of
+//! the primitives this module exports ([`rebuild_nodes`]).
 
 use hive_jobq::TerminalState;