fix: continue scheduled perpetual drains after their cron slot

[atomantic]

Summary

Cron-scheduled perpetual tasks stopped after one successful run: completion refilled through ordinary due-task selection, which rejected the already-consumed cron slot. Carry the completed task type and app into scheduling so that drain can continue between cron slots.

Continuation still requires perpetual mode and respects existing enablement, park, failure, dependency, auto-run, deduplication, and work-detector gates. Other apps and task types retain normal scheduling.

Test plan

• Server: taskSchedule.test.js, cos.test.js, cosTaskGenerator.test.js — 562 tests passed.
• Regression coverage verifies continuation after a consumed cron slot, ordinary cron exclusion, and perpetual/failure parks.
• Reviewed changes for reuse, eligibility gates, scope, and private-data leakage; git diff --check passed.