Add random faction deal and prediction draft

docs/FACTION_ALLOCATION.md

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+# Faction allocation in the lobby
+
+## Sources and scope — 28 October 2026
+
+**Prototyped / Partial.** The user-authorized revised Dune rulebook, physical
+page 4 (printed page 2), gives two initial methods: randomly deal faction
+prediction cards, or draw distinct turn-prediction numbers and select factions
+from highest to lowest. It also permits players to swap factions. The original
+publisher rulebook describes the same selection methods; this prototype exposes
+both in Basic and Advanced and retains the existing direct-choice option.
+
+A host may deal once from all factions belonging to currently enabled families,
+without replacement. Alternatively, the host deals distinct numbers 1–10 to
+seated faction seats. The public draft follows descending numbers, rejects a
+picked or disabled faction and applies all choices together after the last pick.
+These cards represent the setup draw and are not removed from later Bene Gesserit
+prediction. Existing temporary faction selections do not reserve faces during a
+draft. The host may cancel the draft; the previous factions remain. The engine
+uses the existing cryptographic shuffle, event-bound actions and room version
+fencing, and clears human readiness when allocation begins and ends.
+
+For the provisional two-person/four-faction setup, each faction seat receives
+its own draw and pick. That is a software interpretation of the two-faction
+case, not a separate publisher clarification. Seats, credentials, host and
+player-circle positions remain attached to the same participants. AI seats pick
+a legal available faction automatically, preferring their existing faction
+when available. They retain their difficulty and a faction-appropriate name.
+Selection does not bypass any existing expansion/profile start gate.
+
+Nine related unit files pass 43 cases; four isolated HTTP cases include a
+four-seat/two-controller draft, seat selection and game start. These do not
+establish complete setup or deployed acceptance. An isolated browser room also
+exercised a random deal and a human/AI draft to completion.
+
+Consensual faction swaps are not implemented yet. A host's random deal is an
+explicit action and direct selection remains available; neither is a substitute
+for a participant-approved swap. Broader player-count interpretations, complete
+setup combinations, saved-game assurance and deployed acceptance remain open.