Plan the first alpha: scope, waves and exit criteria

The umbrella card for the first alpha test. Write down what the alpha is for and when it is ready, so every other card in the milestone can be cut to fit.

• Question it answers: is the colony loop fun for strangers? Land in Aquais → gather and craft → haul between towns → trade at the pools → hold a plot and build → raid and be raided → die and recover. Sieges, vassals, ships, dungeons and the chain are out of scope.
• Waves: a friends-and-family wave (≈ 20 people, a weekend), then waitlist waves of growing size; how many testers, how long each wave runs, what is wiped between waves.
• Exit criteria per wave: crash-free sessions, server uptime, median session length, how many testers come back the next day, how many complete the loop at least once, the share of bots vs people, the worst economy numbers we accept (inflation, a pool drained to its floor).
• Ready checklist: every high-priority card of this milestone done or explicitly cut.

Done when the plan is a doc on the site (docs/alpha.md), with its decision row, and the milestone's cards are trimmed to it.