hyperhive: make the values the meta-flake render reads swarm-wide

Five host options whose values hive-c0re renders into every agent's
build move under services.hyperhive.swarm, so the swarm states each of
them once instead of every hive carrying its own copy:

  c0re.dashboardPort          -> swarm.dashboardPort
  c0re.claudeCodePackage      -> swarm.claudeCodePackage
  github.enable               -> swarm.github.enable
  otel.collector.port         -> swarm.hiveOtel.collectorPort
  otel.extraResourceAttributes -> swarm.hiveOtel.extraResourceAttributes

Every old path is a mkRenamedOptionModule alias, so a host that sets one
keeps its value and gets an eval warning naming the new path. Types and
defaults are unchanged, so the rendered meta flake, serve.json and
hive-c0re's environment are the same as before on a host that sets
none of them.

The readers move with them: serve.json and its gc-root assertion, the
hive-c0re environment, the hive collector's listen address and bridge
port, the swarm collector's port-collision assertion, and the
claude-login and review-classifier containers' claude pin. The
swarm-services-switch fixture sets the swarm path and now also checks
that serve.json carries the pinned claude.

Part of #4857 (slice 2).

docs/turn-loop/claude-invocation.md

@@ -32,8 +32,8 @@ to the bus.
 harness unit's PATH. By default that's the `claude-code` in the agent's
 own nixpkgs (the meta flake's `nixpkgs` input) via
 `environment.systemPackages`. Since that's typically a release channel and
-this package moves fast, the operator can pin one hive-wide with
-`services.hyperhive.c0re.claudeCodePackage`: hive-c0re writes its
+this package moves fast, the operator can pin one swarm-wide with
+`services.hyperhive.swarm.claudeCodePackage`: hive-c0re writes its
 store path into each agent's flake, and `claude` on PATH becomes a symlink to it
 instead of the container's own `claude-code` — so there's only ever one
 `claude` in the container. Agents pick up a new build on their