hive-c0re: split OpenAPI summary/description, move param docs to params

utoipa splits a handler's doc comment on the first blank `///` line:
everything before it becomes the OpenAPI `summary` (shown in Swagger
UI's collapsed endpoint-list row), everything after becomes the
`description` (only shown once that row is expanded). With no blank
line, the whole doc comment becomes the summary and the description is
empty — which is what every handler in hive-c0re/src/dashboard/ was
doing, so the all-endpoints list showed full multi-sentence prose next
to every route instead of a short one-liner.

For every `#[utoipa::path(...)]`-annotated handler across the 19 files
in that module:

- Inserted a blank `///` line after the first short sentence/clause so
  utoipa's split produces a real summary + description, where the doc
  comment had more to say. Left already-short single-clause docs alone
  (nothing to split).
- Where a query struct derives `IntoParams`, moved param prose that
  duplicated a field's own doc comment out of the handler doc (the
  field already documents itself in the generated spec), or added a
  field doc where the handler explained a param that had none.

No behavior changes — doc comments and `params()` description text
only. Verified `cargo build -p hive-c0re` (clean) and `nix fmt` (zero
changes) after.

Closes #2969

hive-c0re/src/dashboard/topology.rs

@@ -48,6 +48,7 @@ pub(super) struct SetParentBulkEntry {
 }
 
 /// `POST /api/topology/set-parent` — operator-driven parent move.
+///
 /// Form fields: `child` (required, agent name), `new_parent`
 /// (optional — empty / absent string ⇒ promote to root). Refuses
 /// cycles and unknown agents (surfaced async on the job view — this
@@ -102,12 +103,13 @@ pub(super) async fn post_set_parent(
     Ok((StatusCode::OK, "ok").into_response())
 }
 
-/// `POST /api/topology/set-parent-bulk` — move multiple agents in a single
-/// request, producing **one** git commit. JSON body: `[{"child":"name",
-/// "new_parent":"target-or-null"}, ...]`. Empty array is a no-op (200 OK).
-/// First identifier that fails to parse aborts the whole batch before
-/// anything is submitted — a partially-invalid bulk move never reaches
-/// the queue.
+/// `POST /api/topology/set-parent-bulk` — move multiple agents in a
+/// single request, producing **one** git commit.
+///
+/// JSON body: `[{"child":"name", "new_parent":"target-or-null"}, ...]`.
+/// Empty array is a no-op (200 OK). First identifier that fails to
+/// parse aborts the whole batch before anything is submitted — a
+/// partially-invalid bulk move never reaches the queue.
 #[utoipa::path(
     post,
     path = "/api/topology/set-parent-bulk",