fix(cron): skip context files for scheduled jobs

[hughpyle]

Fixes #5209 (at least, fixes "cron jobs fail timeout", which is a reported symptom)

Problem

• The overnight cron jobs failed instead of delivering their reports.

Why 1

• Because the scheduler killed them for inactivity timeout.

Why 2

• Because the jobs spent too long doing non-essential context/workspace discovery instead of the actual task.

Why 3

• Because cron-created agents were still allowed to load or chase local project context:
  • repo-local AGENTS.md / SOUL / memory-file discovery
  • and in one news run, an AGENTS.md file search escalated all the way to path "/"

Why 4

• Because the cron agent setup did not set:
  • skip_context_files=True
• so scheduled jobs inherited normal interactive agent behavior that makes sense for coding sessions, but not for tiny scheduled tasks.

Why 5

• Because cron was using the same broad default agent posture as normal conversations, without sufficiently constraining startup context behavior for automation.

Root cause

• Cron jobs were not isolated from interactive project-context discovery.
• That allowed wasteful local context/tool behavior, which led to long stalls and inactivity timeouts.

Two concrete manifestations

• Watcher cron:
  • wandered into AGENTS/SOUL/local memory-style inspection before checking GitHub Actions
• News cron:
  • explicitly searched "/" for AGENTS.md, which is a terrible idea in a cron run

Fix:

• Skip the context files for cron jobs, light and breezy lemon squeezy

[hughpyle]

closing, done in #7958