drop the applied repo: the hive keeps no copy of an agent's config, only the deploy markers. Refs #5913

docs/agent-lifecycle/persistence.md

@@ -543,12 +543,12 @@ whenever the forge has moved on.
 Isolation still holds by default: a container has its *own* dirs and,
 unless it holds the permission, nothing else.
 
-Under `/var/lib/hyperhive/applied/<name>/` — the hive-c0re-only
-applied repo. Tracks `flake.nix` (module-only boilerplate; never
-edited after first spawn) + `agent.nix` (the actual config; edits land
-here from merged config PRs) + any other files those PRs commit.
-`.git/` carries the proposal / approved / building / deployed / failed /
-denied tag history.
+Under `/var/lib/hyperhive/applied/` — the hive-c0re-only deploy markers
+`.<name>.hyperhive-rev` and `.<name>.config-rev`: the hyperhive and config
+commits the agent's last successful build pinned. No config lives here; the
+forge's `agent-configs/<name>` is the only copy. A hive that predates this
+finds per-agent `applied/<name>` repos here; `migrate::run` deletes them at
+startup.
 
 Under `/var/lib/hyperhive/meta/` — system-level config files, plain state
 with no git history. The flake agents build from is the
@@ -594,7 +594,7 @@ reads it at every container start for `manage_root_agent`.
 `/var/lib/hyperhive/swarm-agent-archetypes.json` holds the archetype each of
 this hive's archetype agents runs, as last read from the swarm's
 `agent-archetype` bucket at the agent's provision and each rebuild. An agent
-with an entry has no `applied/<n>` repo and no `agent-<n>` meta input; see
+with an entry has no config repo and no `agent-<n>` meta input; see
 [archetypes](../swarm/archetypes.md).
 
 hive-c0re creates containers from `internal/meta` (`nixosConfigurations.<n>`).
@@ -607,7 +607,7 @@ an agent's state. The mechanics, for completeness:
 - `DESTR0Y` also drops the systemd drop-in; reviving the agent is
   `swarmctl agent create` with the same name and hive, which reuses the
   kept state.
-- `PURG3` wipes `/var/lib/hyperhive/{agents,applied}/<name>/` — the
+- `PURG3` wipes `/var/lib/hyperhive/agents/<name>/` — the
   union of everything `DESTR0Y` left behind.
 
 `actions::destroy` has no guard for the root/bootstrap agent: it destroys ruth
@@ -636,7 +636,7 @@ until an explicit opt-in upgrade.
   a subvolume root, so purge first calls hive-priv
   (`DeleteAgentSubvolume`) which `btrfs subvolume delete`s it iff it's
   actually a subvolume, then the normal `remove_dir_all` sweep covers
-  plain-dir agents + the applied dir.
+  plain-dir agents.
 
 Per-subvolume disk-usage accounting and optional quotas have since
 landed as the qgroup work: `hivectl quota-enable` turns on btrfs