remove otel.metricIntervalMs and the host-level otel.debug

Both are ignored with a warning through the same shim, now
nix/host-modules/hive-options-removed.nix.

- otel.metricIntervalMs: claude in every agent and hive-c0re's
  container-resource exporter run at the 60s default. The agent-level
  services.hyperhive.agent.otel.metricIntervalMs, set only by the meta
  render, goes too (warning shim in nix/agent-modules/otel-removed.nix).
- otel.debug: services.hyperhive.agent.otel.debug stays, documented and
  set in an agent's own config; the meta render no longer emits it.

nix/agent-modules/claude-settings.nix

@@ -219,7 +219,7 @@ in
           baseClaudeEnv
           // lib.optionalAttrs otelCfg.enable otelSettingsEnv
           // lib.optionalAttrs (otelCfg.enable && otelCfg.debug) {
-            # SDK diagnostics — noisy; only on when services.hyperhive.otel.debug = true.
+            # SDK diagnostics — noisy; only on when services.hyperhive.agent.otel.debug = true.
             CLAUDE_CODE_OTEL_DIAG_STDERR = "1";
           };
       in