Add draft and sealed modes to online multiplayer (desktop)

[MostCromulent]

Apologies to the devs for another huge PR - I think this one is worth it though! 🙏

Phase 1A of #10429 - DESKTOP ONLY
Mobile support will come in follow-up PR once we are happy with architecture and UI flow on this.

Architectural reference document here.

Basic workflow

1. Lobby mode. The online lobby gains a Constructed / Limited mode selector. In Limited mode the host creates an event via a short wizard (Draft or Sealed → pool type → block/set sub-dialogs → pick timer + disconnect grace window for draft). Event config is displayed in a UI panel and visible to all players before they ready up.
2. Pod assembly. Participants are populated from lobby slots; remaining seats are auto-filled with AI for draft; seats are shuffled before start.
3. Run the event.
   • Draft — all human hosts and clients draft simultaneously using the normal draft UI. AI seats pick in between human rounds. Each pack is routed to the correct seat via DraftPackArrivedEvent. A floating picker overlay shows current draft status. Progress of the draft is logged in the Event Log. If a human hits the pick timeout, they will automatically select the first card on their screen and pass their pack.
   • Sealed — host generates pools; each client receives their sealed pool and is dropped into the deck editor to build.

4. Deckbuilding. On draft/sealed completion every participant's pool is saved as a deck on their local device. Each deck is tagged with metadata including event id, format, product (block + set combo), and timestamp. Players are taken immediately to offline deck builder. Players can also access decks later under a shared Draft/Sealed Decks section in multiplayer menu.
5. Match setup
   • If playing immediately after draft, lobby will automatically filter deck selector to match the metadata for the event. The host can disable this with "Only allow decks from this event" checkbox.
   • Alternatively if playing games in separate session from draft, host can load a previous event from the "Setup Event" button, which will let them choose any event matching metadata in decks saved on their device.
   • Standard match procedure follows.

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