fix(cron): add seconds support to parse_duration

[Code-suphub]

Summary

parse_duration only accepts m/h/d units. When the LLM constructs a sub-minute schedule like "10s" or "30s", it raises ValueError, causing the cron job creation to fail silently or produce an incorrect timestamp.

Fixes #44749

Changes

cron/jobs.py:

1. parse_duration — Add s/sec/secs/second/seconds to the regex and multiplier map ('s': 1/60). Return value remains in minutes (fractional for sub-minute) to preserve backward compatibility.

2. parse_schedule — Use timedelta(seconds=total_seconds) instead of timedelta(minutes=minutes) for sub-minute precision. Update display text and error message to include seconds examples.

3. Interval display — Show "every 30s" instead of "every 0.5m" for sub-minute recurring schedules.

Examples

"10s"       → once in 10 seconds
"30s"       → once in 30 seconds
"every 30s" → recurring every 30 seconds
"30m"       → once in 30 minutes (unchanged)
"2h"        → once in 2 hours (unchanged)

Testing

cd hermes-agent && python -m pytest tests/cron/test_jobs.py -v -k "parse"

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Checklist

Code

• I have read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope): description)
• I searched for existing PRs to make sure this is not a duplicate
• My PR contains only changes related to this fix (no unrelated commits)
• I have considered cross-platform impact (Windows, macOS, Linux) per the compatibility guide

Documentation

• I have updated relevant documentation or marked as N/A
• I have updated cli-config.yaml.example if I added/changed config keys or marked as N/A

[tonydwb]

Good feature addition. Adds seconds support to parse_duration for sub-minute cron intervals. Return type changed from int to float. All usages updated to handle fractional minutes (max(1, round(minutes * 60)) ensures sub-minute intervals work correctly). No issues found.

[alt-glitch]

Duplicate of #44751 (earlier open, same author) — same fix for #44749: add seconds units to parse_duration. #44751 also adds LLM guidance away from absolute timestamps.

[teknium1]

Thanks for addressing the relative-duration parser gap.

Problems

• This does not yet provide sub-minute execution: the built-in ticker is explicitly 60 seconds in cron/jobs.py:85, and cron/scheduler_provider.py:176-194 runs one tick then waits that interval. A parsed 10s job can therefore be discovered up to roughly a minute later.
• The proposed fractional minutes representation also reaches blueprint export. tools/blueprints.py:261 calls _schedule_to_string, where int(schedule["minutes"]) at line 314 turns a 30-second interval (0.5) into 0 and renders every 0h at lines 315-317.
• The diff changes no tests; current parser coverage in tests/cron/test_jobs.py:33-113 has no seconds cases.

Suggested changes

• Establish a scheduler-level sub-minute dispatch contract before accepting seconds syntax, then preserve that representation through serialization and add deterministic parser, scheduling, and export regression tests.

Automated hermes-sweeper review.