I want: player contracts

Edition: Premium only.

Steps

1. Confirm Premium jar.
2. Edit fees / cooldowns in contract-request.yml, /sq reload.
3. Players use /sq contract or the browser, or staff link a Citizens broker (/sq npc broker).
4. Walkthrough: Contract NPC Setup.

Verify

Check	Passes when
Board	Difficulty picker and fee show before pay
Paper	Taker gets a locked contract paper
Free jar	Contract commands unavailable

Guide: Contract Request
Defaults: Default contract-request.yml