(MODULES-11982) Stagger nightly cron to 00:50 UTC

[imaqsood]

Strategy and full slot table: Supported modules: staggered nightly schedule

Summary

Moves the puppetlabs-java nightly workflow from 0 0 * * * to 50 0 * * * (00:50 UTC). Only the cron: line in .github/workflows/nightly.yml changes; the triggers and jobs are untouched.

This module renders nightly.yml from pdk-templates (unmanaged: false), so .sync.yml also gets cron: '50 0 * * *' under .github/workflows/nightly.yml. That keeps the slot after a future pdk update once pdk-templates supports the key (puppetlabs/pdk-templates#677). Until then PDK ignores the key, so it's harmless.

Additional Context

• Root cause: all 40 supported modules start their nightly at 00:00 UTC. That sends about 467 provision_service VM requests at once and hit the GCP FIREWALLS quota on 2026-10-01 (389 provision failures).
• Approach: each module gets its own 15-minute slot between 00:05 and 04:50 UTC. Slots are weighted by VM count, so at most 4 nightlies and 50 VM requests start in any 30 minutes. This module has about 7 VM jobs per night. Slots avoid :00 because GitHub delays top-of-hour schedules the most.
• This PR is part of wave 2a (16 Linux/cross-platform modules). Wave 1, the 12 heaviest modules, is MODULES-11968 and still in review; please merge this after the wave-1 PRs land.

Related Issues (if any)

• Jira: MODULES-11982 (split from MODULES-11968)
• pdk-templates cron key: (MODULES-11968) Make the nightly workflow cron configurable pdk-templates#677
• Related: MODULES-11966 (CAT cleanup of leaked firewall rules), MODULES-11965 (provision retry)

Checklist

• 🟢 Spec tests. (Not affected; this PR's ci.yml run covers it)
• 🟢 Acceptance tests. (The nightly itself only runs on schedule; check the first run after merge starts at 00:50 UTC)
• Manually verified: exactly one cron line changed in nightly.yml, plus one cron: line in .sync.yml. Both files parse with ruby -ryaml, and the parsed values equal 50 0 * * *.

🤖 Generated with Claude Code