docs(agents): facts pass on agent-hierarchy.md and mcp.md

mcp.md:
- matrix and subagent extra MCP servers are http (hive-matrix-daemon,
  hive-subagent-daemon), not stdio; screen is the one entry that still
  uses the stdio default (nix/agent-modules/matrix.nix:290-297,
  screen.nix:22-25)
- set_status is always-on, not meta-group-gated; mark_todos_done (also
  always-on) was undocumented (hive-sh4re/src/permissions.rs:151,
  hive-agent-mcp/src/mcp/mod.rs:425)
- System messages: HelperEvent has 3 variants, not the 8 previously
  listed; ApprovalResolved/ContainerCrash routing and the swarm-wide
  NATS notices stream (swarm_notices.rs) replace the old per-agent
  todo-wake description for rebuilt/killed/destroyed/logged_in/needs_login
- get_loose_ends's approval rows are manager-only; PendingMessages and
  UnreadMatrix were missing from the description
  (hive-sh4re/src/inbox.rs:127-184)
- subagent spawning runs on hive-runtime (claude or ACP), not
  claude-only (hive-subagent-mcp/src/session.rs:77)
- Waking section: matrix/bash/forge all moved to the in-agent todo
  socket; the host Wake request has no built-in caller left today

agent-hierarchy.md:
- distinguished the swarm-wide agent roster (swarm-controller's
  identity store, authoritative) from the hive-local topology.json
  (a derived, reconciled cache scoping ManageRootAgent's bind-mounts),
  linking README's framing
- noted services.hyperhive.ruthless (a hive can run with no manager at
  all)
- Wire-protocol bullet: the only privileged Request variants left are
  the scheduling ops; Kill/Start/Restart/Update/GetLogs don't exist on
  this socket
- Prompt/tools: prompt::render hardcodes the agent role for every
  container today (role:manager blocks are dead code); the tool
  allow-list has no Flavor switch, it's HIVE_TOOL_GROUPS same as any
  agent

Not touched: agent-hierarchy.md:140-200 (Harness systemd unit shape,
kept in place — see PR follow-ups) and docs/agent-lifecycle/approvals.md
(blocked on #4853).

docs/agent-lifecycle/agent-hierarchy.md

@@ -15,17 +15,33 @@ cleanup.
 
 ## Where the roster lives
 
-The roster lives in the hive-c0re-owned **meta repo**, alongside
-`flake.nix`, at `/var/lib/hyperhive/meta/topology.json`:
+"The roster" means two different, non-overlapping things depending on
+scope. The [README](../../README.md)'s control-plane row ("`swarm-controller`
+holds the hive directory, the agent roster and the job graph") is the
+**swarm-wide** one: `GET /api/agents` on swarm-controller reads
+straight from the swarm's authelia identity store over
+`swarm-authelia-bridge` (`swarm-controller/src/auth.rs::list_agent_identities`)
+— "every agent the swarm holds an identity for" (`swarm-controller/src/main.rs`'s
+`get_agents` doc comment). It's authoritative: an agent exists in the
+swarm if and only if it has an identity there, and `swarmctl agent
+create` (or the swarm UI, via `POST /api/agents`) writes that identity
+once, by calling `ensure_agent_identity`.
+
+This page is about a different, **hive-local** file: the hive-c0re-owned
+**meta repo**, alongside `flake.nix`, at
+`/var/lib/hyperhive/meta/topology.json`:
 
 ```json
 ["alice", "bob", "ruth"]
 ```
 
-One entry per agent the hive knows about, in name order. The file
-carries no per-agent value any more, and encodes no ordering or
-grouping — it answers exactly one question, _which agents exist,_ and
-`topology::all_agents` is the only reader that matters.
+One entry per agent _this hive_ currently has state/config for, in name
+order. Unlike the swarm roster, nothing writes this file directly —
+it's a derived cache, rebuilt by the reconcile pass below from what the
+hive observes locally (config repos cloned, containers spawned), and it
+answers a narrower question than "does this agent exist": _which of
+this hive's local agents the `ManageRootAgent` capability's bind-mounts
+should cover._ `topology::all_agents` is the only reader that matters.
 
 That reader is a permission boundary: the set it returns is what an agent
 holding the `ManageRootAgent` capability gets bind-mounted (each other
@@ -93,7 +109,10 @@ consequence of removing the field, not a side effect of it.
 
 Capability enforcement isn't fully wired yet, so the
 **manager (`ruth`) still gets some hard-coded special treatment**
-other agents don't:
+other agents don't. A hive can opt out of having one at all
+(`services.hyperhive.ruthless = true` skips `hive-c0re`'s root-agent
+create/start sweep entirely, `hive-c0re/src/workers/auto_update.rs`);
+everything below applies only when it doesn't:
 
 <!-- vale write-good.Passive = NO -->
 
@@ -103,14 +122,20 @@ other agents don't:
   approval step — every other agent is created at swarm level
   (`swarmctl agent create`).
   Roster-wise, `ruth` is just another entry.
-- **Wire-protocol** — the privileged `Request` variants
-  (`Kill` / `Start` / `Restart` / `Update`; `GetLogs`) — marked
-  `*(privileged)*` in `hive-core-agent-sock`'s unified `Request` enum —
-  are reachable only from the manager's socket flavour today; each is
-  planned to become a capability check. One exception: `Wake` (inject a `from: <X>` message into the
-  caller's own inbox) isn't really privileged — every per-agent daemon
-  (for example `hive-forge-notify`) needs it, and sub-agents already have the
-  equivalent on their own socket.
+- **Wire-protocol** — the only `*(privileged)*` `Request` variants left
+  in `hive-core-agent-sock`'s unified enum are the scheduling ops
+  (`RequestSchedulePrompt`, `CancelSchedule`, `FireScheduleNow`,
+  `EditSchedule`), reachable only from the manager's socket flavour
+  today, matching the `scheduling` tool group
+  ([`docs/turn-loop/mcp.md`](../turn-loop/mcp.md)). Container lifecycle
+  ops (kill/start/restart/rebuild) never lived on this socket — they go
+  through the separate host-admin socket `hivectl` speaks. `Wake`
+  (inject a `from: <X>` message straight into the caller's own inbox)
+  is on this socket too but isn't privileged to either flavour; no
+  built-in in-container producer calls it today — matrix, bash and
+  forge notifications all moved to pushing a todo on the harness's
+  in-agent socket instead (see
+  [`docs/turn-loop/mcp.md`](../turn-loop/mcp.md#waking-the-agent-from-inside-the-container)).
 - **Storage/mounts** — only the manager container gets
   `/var/lib/hyperhive/agents` bind-mounted RW at `/agents` (so it can
   manage any agent's state dir — config isn't authored there, since a
@@ -122,12 +147,20 @@ other agents don't:
   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.
-- **Prompt/tools** — the system prompt uses `<!-- role:agent -->` /
-  `<!-- role:manager -->` marker blocks, and a `Flavor::{Agent,
-Manager}` switch picks the MCP tool allow-list claude sees. Both are
-  already parametrised on a single flavour value, so the planned
-  per-capability-group version (`cap:<group>` prompt blocks + a
-  matching tool allow-list) is additive rather than a rewrite.
+- **Prompt** — _not_ treated differently in practice any more: `prompts/system.md`
+  still carries `<!-- role:agent -->` / `<!-- role:manager -->` marker
+  blocks, but `prompt::render` filters for `"agent"` unconditionally for
+  every container, manager included ("always `agent` role — there is
+  only one role", `hive-agent/src/prompt.rs`'s own module doc). The
+  `role:manager` blocks are dead in production, exercised only by a
+  unit test (`filter_role_blocks(SAMPLE, "manager")`).
+- **Tool allow-list** — also not a flavour switch: the MCP tools claude
+  sees come from `HIVE_TOOL_GROUPS` alone, the same mechanism for every
+  agent ([`docs/turn-loop/mcp.md`](../turn-loop/mcp.md)). Ruth's wider
+  default surface is just a wider default grant
+  (`ToolGroup::MANAGER_DEFAULT`, seeded by `auto_update.rs` whenever its
+  groups aren't already set), not anything keyed off its name or
+  container.
 - **State dirs** — _not_ special-cased: `HYPERHIVE_STATE_DIR` is
 injected uniformly via `systemd.globalEnvironment` for every
 container including the manager, so all token/state paths resolve