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).

nix/agent-modules/otel.nix

@@ -125,7 +125,7 @@ in
         Extra comma-separated entries appended to
         `OTEL_RESOURCE_ATTRIBUTES` after the built-in
         `service.name` / `agent` / `swarm` labels.
-        Host-driven via `services.hyperhive.otel.extraResourceAttributes`.
+        Host-driven via `services.hyperhive.swarm.hiveOtel.extraResourceAttributes`.
       '';
     };