Fix CI failures on mvp-external-batch-fixes (all 3 jobs)

[brianlball]

Fixes the three failing jobs in run 30320382392. All failures were introduced on this branch; develop is green.

linux-test / macos-test

1. Nomad spec rewritten to match submit_nomad.rb's real contract
The spec stubbed a nomad CLI and passed --nomad-cmd, but submit_nomad.rb has no such option — it drives the Nomad HTTP API (POST /v1/jobs/parse → POST /v1/jobs) and lays out the shared location as <loc>/analysis_<id>/{package,results} (the spec expected analysis_runs/runs/...). This was masked by a second bug: the stub was written with an interpolating heredoc, so unescaped #{output_flag} raised NameError in the before hook and killed all 3 examples before the mismatch could surface. The spec now stubs the HTTP API with a minimal in-spec TCPServer, asserts on the rendered HCL (count, job name, package/results URIs), and runs the full package → submit → array-tasks → sync → ingest pipeline.

2. sync_results.rb: NFS branch no longer requires rsync
The local/NFS path shelled out to rsync; on hosts without it the sync loop spun forever (--interval 0). Local mirroring is now in-process FileUtils.cp_r; S3 and SSH branches are unchanged.

3. Ruby LHS backend: preflight histogram attach is non-fatal
sample_all_variables attaches the generated histogram via PreflightImage.add_from_disk, which runs paperclip styles through ImageMagick identify — not installed on ubuntu-24.04/macos-15 runner images or PAT-local hosts. The attach is now wrapped in a rescue (warn + continue), so sampling degrades gracefully instead of failing the analysis. This is what broke all 5 sampling_lhs_spec examples.

docker

4. Restore the CRAN snapshot pin in docker/R/install_packages.R
This branch reverted the date-frozen Posit snapshot (ba21522) back to cloud.r-project.org, which picked up RcppParallel 6.1.1 — its configure needs cmake, so RcppParallel → dtwclust → sensitivity cascaded and the rserve image build died. Restored develop's pinned version; the snapshot serves prebuilt jammy binaries, no cmake needed.

Verification

• sampling_lhs_spec + external_batch_nomad_spec + external_batch_aws_spec + external_batch_spec: 30 examples, 0 failures (local-test env, on a host without ImageMagick, so the rescue path in fix 3 is genuinely exercised)
• Fresh Rscript install_packages.R inside nrel/openstudio-r:4.4.0: exit 0; RcppParallel/dtwclust/sensitivity install as snapshot binaries

Note: this branch forked from 5554f4a and is 7 commits behind develop; a rebase is worth doing regardless (it also dropped the rserve CI caching from ba21522's workflow changes).

🤖 Generated with Claude Code

[brianlball]

Superseded by #856, which rebuilds mvp-external-batch-fixes on current develop. This branch was based on develop-as-of-#840: it duplicated the external-batch work that merged as #842 and was missing #844–#853, and its linux/macos failures were caused by the branch's own bin/openstudio_meta bundler config-set rewrite (test-phase bundle config poisoned the export phase). #856 keeps the Nomad/Ansible work (original authorship), the nomad spec rewrite and CI fixes from this PR, and drops the 3.10.0/mongo-6 downgrades and the openstudio_meta rewrite.