hive-c0re: drop redundant METHOD/path prefixes from OpenAPI summaries

Swagger UI's endpoint-list row already shows the HTTP method badge +
path for every row, so restating `METHOD /path` at the start of a
handler's own summary is pure duplication. Strips that self-referential
prefix from every summary that has it and re-capitalizes what follows
as a standalone sentence.

Left two false positives untouched: misc_api.rs's operator-inbox
summary cross-references a *different* sibling endpoint
(mark-all-read) for context, and topology.rs's SetParentForm struct
doc happens to mention its endpoint's path but isn't a handler summary
line. Both are legitimate, not redundant.

hive-c0re/src/dashboard/tombstones.rs

@@ -104,7 +104,7 @@ pub(crate) async fn emit_tombstones_snapshot(coord: &Arc<Coordinator>) {
     });
 }
 
-/// `POST /api/purge-tombstone/{name}` — wipe a tombstoned agent's
+/// Wipe a tombstoned agent's
 /// retained state dir + applied config dir entirely.
 #[utoipa::path(
     post,