Delete nix/templates/ruth.nix, the ruth nixosConfiguration, module and
toplevel, the hive-c0re managerToplevel option, and the meta flake's
isManager switch with lifecycle::MANAGER_NAME. Every agent, ruth
included, now builds from nix/templates/agent.nix. The template's only
content beyond agent.nix was docs.enable = mkDefault true; docs.enable
is off by default for every agent and ruth's own agent.nix turns it on.
Refs #5377
Every per-agent harness option lived at the top-level `hyperhive.*` while
the host tier has always been `services.hyperhive.*`. Move all 52 agent-tier
option leaves (33 top-level names across 16 modules) to
`services.hyperhive.agent.*`, repoint every read, and keep existing agent
configs evaluating through one `mkRenamedOptionModule` per old leaf path in
the new nix/agent-modules/renamed-options.nix.
The shims are per leaf rather than per namespace: `user`, `mcp`, `otel`,
`queue`, `docs`, `forge`, `frontend`, `github`, `gui`, `logs`, `matrix` and
`cargo` are plain attrsets of declarations, not submodule-typed options, so
a parent-path rename would not reach their children. Three read-only
options (`frontend.mergedDist`, `queue.clientIdFile`,
`queue.clientSecretFile`) deliberately get no shim — a rename contributes a
definition, which a read-only option refuses; the exclusions are commented
in place.
Refs #4473
