fix tracker-tag lint and vale prose reds on #4624

Rewrite two bare issue references (#4472, #4477) as self-standing
prose per check-issue-refs.sh's requirement — no markdown exemption,
hash-number tags are dead weight to a public forge-mirror reader.

Apply iris's vale fix to docs/agent-lifecycle/approvals.md (passive
voice, two contractions, one auto- hyphenation).

hive-c0re/src/lifecycle/host_config.rs

@@ -334,7 +334,7 @@ async fn set_nspawn_flags(
     // accident of how the set is computed. The grant used to hang off a
     // `can_manage_top_level_agents` role and cover `top_level_agents()`
     // — i.e. `parent.is_none()` — which was "everything outside the
-    // hierarchy". With the hierarchy gone (#4472) every agent is
+    // hierarchy". With that hierarchy removed, every agent is
     // parentless, so that set *was* every agent anyway; the capability
     // now says so out loud instead of deriving it from a field that no
     // longer discriminates.