docs(agent-hierarchy): mark section D done — legacy /state mount dropped (#604)

docs/agent-hierarchy.md

@@ -145,14 +145,16 @@ Tree-shape version:
 - `request_update_meta_inputs` is the only path that actually writes
   `flake.lock`, gated by the cap; everyone else stays RO.
 
-### D — drop legacy `/state` for manager
+### D — drop legacy `/state` for manager ✓ done (#604)
 
-`lifecycle.rs::notes_mount` currently ternary's `/state` for the
-manager and `/agents/<name>/state` for everyone else (because the
-manager pre-dates the per-agent state-dir layout). Milestone bullet:
-unify on `/agents/<name>/state` for everyone. One-time `mv` of
-`/var/lib/hyperhive/manager/state` → `/var/lib/hyperhive/agents/manager/state`
-in `migrate.rs` (idempotent, marker-guarded).
+`lifecycle.rs` no longer binds `/state` for the manager.
+`HYPERHIVE_STATE_DIR` is now injected uniformly via
+`systemd.globalEnvironment` in `meta.rs` for every container
+(manager included), so all token/state paths resolve through
+`$HYPERHIVE_STATE_DIR`. The harness-base shell scripts
+(tea-login, forge-avatar-sync, matrix-avatar-sync) simplified
+from glob+for loops to a direct `$HYPERHIVE_STATE_DIR/<token>`
+read.
 
 ### E — prompt + tools