Clear the allocation

Auto-allocate fills every empty seat. There is no way back to an empty room, so trying a second arrangement means reloading and losing the guest list with it.

Acceptance criteria

• A clear control on the plan screen returns seated guests to the unseated rail
• Pinned guests stay where they are. Pinning is the decision the person has already made, and clearing an allocation is not a reason to throw it away
• Clearing the pins as well is a separate action, worded so the difference is obvious
• Both ask first. Undo is not in the MVP, so neither is recoverable
• Neither is a primary button. Auto-allocate is the only filled action on the plan screen
• The header counts for pinned and unseated update with it, and the violations panel recalculates

Notes

KB-1 has pinning as the idea the product turns on: the tool does the boring ninety percent around the decisions already made. A clear that discards the pins discards the decisions, which is why the two are separated rather than being one button.