Add harvester auto-resume

[schultzp2020]

Adds automatic harvesting resumption for idle harvesters. When a harvester becomes idle (e.g., after completing a move order), it will automatically resume harvesting after a configurable delay.

User story:
As a player, I want my harvesters to automatically resume harvesting after I move them out of danger or slightly misclick, so that I don't lose income from forgetting to re-issue harvest orders.

Behavior:

• After a harvester becomes idle for any reason, it waits a configurable delay then automatically queues a new harvest order
• Default delay is 250 ticks (~10 seconds at normal game speed), giving the player time to issue follow-up orders
• Works for all idle scenarios: completed move orders, attack orders, scatter, stop, etc.
• Full harvesters will route to a refinery to unload first (handled by existing FindAndDeliverResources logic)
• Implemented as a standalone conditional trait (HarvesterAutoResume) — can be disabled per-unit via conditions
• Configurable via YAML: ResumeDelay