deploy: give every option an enable, and name the controller one

Two corrections from review, applied forward on this branch rather than
by rewriting it.

`deploy.<service>` was a bare bool, which makes
`deploy.forgejo = { enable; ci; }` unrepresentable -- the nested
CI-runner sub-option this namespace was designed around. Every entry is
now an attrset with an `enable`, so a second per-host deployment
decision becomes an ordinary addition rather than a migration.

`deploy.controller` is now `deploy.swarm-controller`, consistent with
`deploy.swarm-ui`, which was introduced in the same commit.

89 references rewritten across 24 files -- nix, Rust, docs, and the
repo's own CLAUDE.md.

The prefix-anchored sweep missed exactly one, and it was live code:
hive-tls.nix spells it `hyperhiveCfg.deploy.controller` -- the only
`hyperhiveCfg` prefix among 45 references. A suffix grep
(`\.deploy\.<name>`) finds it; a path-anchored one cannot, because the
head of a reference is whatever alias the reading file happens to bind.

nix/host-modules/hive-tls.nix

@@ -669,6 +669,6 @@ in
     # in review on this PR; it evaluates and builds clean either way, which
     # is exactly why it needed a reviewer rather than a check.
     systemd.services.swarm-controller.environment.SWARM_CONTROLLER_OIDC_CA_FILE =
-      lib.mkIf hyperhiveCfg.deploy.controller "${cfg.stateDir}/trust-bundle.pem";
+      lib.mkIf hyperhiveCfg.deploy.swarm-controller.enable "${cfg.stateDir}/trust-bundle.pem";
   };
 }