document reading and editing an agent's agents.md through the swarm

docs/swarm/README.md gets the routes, the revision, the apply semantics
and the stopped-agent behaviour; the persistence doc points there from
the AGENTS.md entry. The swarm-controller, swarm-controller-api and
swarmctl READMEs and the repo map in AGENTS.md list the new bodies and
routes. docs/tools/swarmctl-cli.md is regenerated for
`swarmctl agent agents-md`, whose help text loses two passive phrasings
vale flags.

swarm-controller/README.md

@@ -58,6 +58,12 @@ The swarm's control plane. The swarm UI and `swarmctl` are its clients.
   (`GET`/`PUT`/`DELETE /api/agents/{name}/limits`); the hive running the
   agent reads it, and each cap replaces the hive's own answer for that field →
   [`docs/scheduler/coordinator.md`](../docs/scheduler/coordinator.md#container-resource-limits).
+- **Agent instructions** — each agent's `AGENTS.md` as its harness last
+  published it into the `agents-md` KV bucket
+  (`GET /api/agents/{name}/agents-md`), and edits to it as git diffs, which
+  this daemon hands to the agent's harness to apply
+  (`PUT /api/agents/{name}/agents-md`) →
+  [`docs/swarm/README.md`](../docs/swarm/README.md#an-agents-agentsmd).
 - **Review classifier** — try-outs from the swarm UI and reviews on review
   requests, and the newest 100 finished runs, one document in the
   `review-classifier-runs` KV bucket, which this daemon alone writes