docs+comments: say what changed instead of tagging the tracker item

The prose added by this branch named the tracker item in seventeen
places, which check-issue-refs.sh rejects: a `#N` tag is dead weight for
anyone reading the public mirror, where no issue data exists. Each one
now states the fact it was pointing at — the parent field is gone — so
the sentence stands on its own.

Two of those lines also carried a rustdoc break: `[`write`]` in
topology.rs is ambiguous between the module's own `write` fn and the
`write!` macro, which `-D rustdoc::broken-intra-doc-links` fails. Spelled
`[`write()`]`, per rustdoc's own suggestion.

The host_config.rs rewrite is two lines rather than three so the doc
block stays under check-comment-blocks.sh's 30-line ceiling.

docs/agent-lifecycle/agent-hierarchy.md

@@ -2,8 +2,8 @@
 
 <!-- vale write-good.Passive = NO -->
 
-Agents are a **flat set**, with no parent/child tree: #4472 removed the
-`parent` field `topology.json` used to carry, and every mechanism that
+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.
 
@@ -33,7 +33,7 @@ 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 pre-#4472 format
+### Reading the legacy 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

docs/agent-lifecycle/persistence.md

@@ -344,8 +344,8 @@ The RW on `state` is deliberate, not an oversight: the holder recovers
 other agents, which includes writing into their state (for example
 seeding notes, clearing a stuck sentinel) as well as reading it.
 
-This is the **only** cross-agent mount. #4472 removed the topology
-parent field, and with it the unconditional grant every agent used to
+This is the **only** cross-agent mount. Dropping the topology parent
+field took with it the unconditional grant every agent used to
 get over its own direct children — an agent holding no capability now
 sees its own dirs and nothing else.
 
@@ -395,8 +395,8 @@ Contents:
 - `topology.json` — the agent roster (`["alice", "bob", "ruth"]`).
   Written by `topology::reconcile` on every meta sync; read by
   `topology::all_agents`, which is the set the `ManageRootAgent`
-  capability grants mounts over. Carried a `parent` per agent until
-  #4472; the reader still accepts that shape and keeps its keys.
+  capability grants mounts over. Carried a `parent` per agent in the
+  legacy format; the reader still accepts that shape and keeps its keys.
 - `tool-groups.json` — per-agent MCP tool group grants
   (`{ "alice": ["messaging", "inbox", "execution"] }`). Written by
   `tool_groups::set_groups`; injected as `HIVE_TOOL_GROUPS` env

docs/process/conventions.md

@@ -89,8 +89,8 @@ angle-bracket and asterisk shapes below are structurally safe.
   inbox view; no agent ever `recv`'s them.
 
 `<parent>` and `<children>` were two more, resolved against a
-`topology.json` parent field. #4472 removed that field and both
-sentinels with it: address `operator` where you would have said
+`topology.json` parent field. That field and both sentinels no longer
+exist: address `operator` where you would have said
 `<parent>`, and name the recipients (or broadcast to `*`) where you
 would have said `<children>`. Nothing rewrites a recipient at send time
 any more — what an agent passes is what the broker stores.

docs/web-ui/dashboard.md

@@ -59,8 +59,8 @@ surfaces, not tab panes.
 **C0NTAINERS** — live containers rendered as a flat,
 alphabetically-sorted list. The renderer still walks
 `ContainerView.parent` for a depth-first tree with ASCII glyphs
-(`├─`, `└─`, `│  ` continuation columns), but #4472 removed that field,
-so every row sits at depth 0 and the renderer paints no glyph. The tree
+(`├─`, `└─`, `│  ` continuation columns), but that field no longer
+exists, so every row sits at depth 0 and the renderer paints no glyph. The tree
 sorts alphabetically;
 roots likewise. The tree tolerates cycles in the parent graph —
 it appends orphaned containers (not reachable from any root)
@@ -981,7 +981,7 @@ identically.)
 
 ### Topology tree
 
-⚠️ **Dormant since #4472,** which removed `ContainerView.parent`:
+⚠️ **Dormant now that `ContainerView.parent` no longer exists:**
 `buildAgentTree` now puts every container at depth 0 and the rules below are
 all no-ops — the list renders flat. The walk and the prefix painting are
 still in `swarm.js`; retiring them falls to the frontend owner rather
@@ -1032,8 +1032,8 @@ frosted-mauve bar slides up from the bottom of the viewport
   - `DESTR0Y` / `PURG3` — always available
 <!-- vale write-good.Passive = YES -->
 
-  #4472 removed the `M0V3` picker that used to sit here — an agent has
-  no parent to move it to any more.
+  The `M0V3` picker that used to sit here no longer exists — an agent
+  has no parent to move it to any more.
 - **`✕ clear`** button + `Esc` key clear the entire selection.
 
 Every render prunes stale selections (agents destroyed while