docs(agents): drop nonexistent-thing mentions, state current behaviour

docs/agent-lifecycle/agent-hierarchy.md

@@ -2,16 +2,15 @@
 
 <!-- vale write-good.Passive = NO -->
 
-Agents are a **flat set**, with no parent/child tree: the `parent` field
-`topology.json` used to carry is gone, along with every mechanism that
-read it. The capability store scopes which agents can manage which
-others; a tree position no longer scopes anything.
+Agents are a **flat set**, with no parent/child tree: `topology.json`
+carries no `parent` field, and the capability store — not tree
+position — scopes which agents can manage which others.
 
 <!-- vale write-good.Passive = YES -->
 
-This doc covers what the roster file is now, what the removal took with
-it, and where the manager still gets special-cased, as a tracked
-cleanup.
+This doc covers what the roster file holds today, the map-shaped
+alternative `topology::all_agents` still accepts, and where the manager
+still gets special-cased, as a tracked cleanup.
 
 ## Where the roster lives
 
@@ -49,11 +48,11 @@ agent's `state` read-write and `config` read-only; never `harness`). An
 agent holding no capability sees its own dirs and nothing else. See
 [`persistence.md`](persistence.md)'s _Cross-agent access to state._
 
-### Reading the legacy format
+### Reading the map-shaped format
 
-`topology.json` used to be a map of `name → parent | null`. The reader
-still accepts that shape and keeps its keys, so a hive upgrading across
-the change reads the same roster rather than an empty one. An empty
+`topology.json` may also be a map of `name → parent | null`; the reader
+accepts that shape too and keeps its keys, so a hive with a file in that
+shape still reads the same roster rather than an empty one. An empty
 roster costs more than a cosmetic gap: every capability holder loses its
 mounts until the next reconcile pass writes the array form.
 
@@ -79,7 +78,7 @@ from which agents exist, so the next pass overwrites a hand edit.
 See `hive-c0re/src/agent_config/topology.rs` and `hive-c0re/src/meta.rs`'s
 module docs for the exact call chain.
 
-## What the parent field used to do
+## What replaced the parent field
 
 Recorded so a reader who finds one of these in an old branch, an issue
 thread or a stale comment knows each one went away rather than moved:
@@ -98,10 +97,10 @@ thread or a stale comment knows each one went away rather than moved:
 
 <!-- vale write-good.Passive = NO -->
 
-The last row is the one with teeth: an agent that used to reach a child's
-state dir by virtue of being its parent no longer reaches it at all
-unless it holds `ManageRootAgent`. That narrowing is the intended
-consequence of removing the field, not a side effect of it.
+The last row is the one with teeth: reaching a child's state dir
+requires holding `ManageRootAgent`; parentage grants nothing. That
+narrowing is the intended consequence of removing the field, not a
+side effect of it.
 
 <!-- vale write-good.Passive = YES -->
 
@@ -141,12 +140,11 @@ everything below applies only when it doesn't:
   manage any agent's state dir — config isn't authored there, since a
   real config change is a PR from a clone), plus RO mounts for
   `/applied` (diff against what's deployed) and `/meta` (system-wide
-  deploy log). That grant is the `ManageRootAgent` capability now, and
-  ruth holds it; no name check remains. hive-c0re will
+  deploy log). That grant is the `ManageRootAgent` capability, which
+  ruth holds; nothing checks the agent's name. hive-c0re will
   gate RO `/meta` access on a "meta read" capability; no agent-facing
-  path writes `flake.lock` any more — `request_update_meta_inputs` was
-  removed, leaving the operator dashboard's `POST
-/api/meta-update` as the only entry point.
+  path writes `flake.lock` — the operator dashboard's `POST
+/api/meta-update` is the only entry point.
 - **Prompt** — treated identically: `prompt::render` always filters for `agent`. `prompts/system.md`
   still carries `<!-- role:agent -->` / `<!-- role:manager -->` marker
   blocks, but `prompt::render` filters for `"agent"` unconditionally for