feat(arena-colosseum): 2-pick + curated deck sources (phase 3)

Closes the family. arena-colosseum 10/16 → 15/16 zero stubs (the 16th —
finish_load — is dead per project_dead_battle_endpoints).

* 2-Pick draft lift onto ArenaColosseumController:
  - get_candidate_classes samples from ArenaTwoPickConfig.AllowedClassIds
    and persists the slate onto the run.
  - class_choose accepts class_id XOR chaos_id; both populate run.ClassId,
    chaos branch stores ChaosId for replay.
  - get_candidate_cards is the idempotent draft-resume snapshot.
  - card_choose appends both cards from the picked pair, advances turn 1..15.
  - Pool override: ArenaTwoPickCardPoolService gets a non-breaking
    GeneratePickSetsForTurn(..., poolCardSetIds) overload; Colosseum routes
    pass ColosseumSeasonConfig.PoolCardSetIds (falls back to challenge →
    rotation when empty).
* Curated-deck schema: ColosseumHofDeck / ColosseumWindFallDeck /
  ColosseumAvatarDeck — three identical tables (separate per per-pool
  operational lifecycle), unique on DeckNo. Migration AddColosseumCuratedDecks.
* IColosseumCuratedDeck interface + a generic ColosseumCuratedDeckImporterBase<T>
  with three concrete subclasses (HOF / WindFall / Avatar), registered in
  Bootstrap. Seed files ship empty.
* 6 curated endpoints on ArenaColosseumController: get_{hof|windfall|avatar}_deck_list
  return BARE-ARRAY data per spec; register_{hof|windfall|avatar}_deck share
  one generic RegisterCuratedAsync<T> dispatcher. Cross-pool register
  rejected via per-pool lookup. Curated register has no is_published flag
  (constructed-only) — clears the run's flag for state consistency.
* Tests: 5 draft HTTP tests + 11 curated-deck HTTP tests (4 parameterized
  3 ways across HOF/WindFall/Avatar + a cross-pool isolation test + an
  is_published clear test). Existing TwoPick service tests updated for the
  new pool overload. Full suite: 1347/1347.

Phase 3 ship gate met. Branch ready for merge.

SVSim.Database/Models/ColosseumAvatarDeck.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Curated Avatar (themed-character) deck for Arena Colosseum. See
+/// <see cref="ColosseumHofDeck"/> for the rationale on the duplicated schema.
+/// </summary>
+public class ColosseumAvatarDeck : IColosseumCuratedDeck
+{
+    public long Id { get; set; }
+    public int DeckNo { get; set; }
+    public int ClassId { get; set; }
+
+    [Column(TypeName = "jsonb")]
+    public string CardListJson { get; set; } = "[]";
+
+    public long SleeveId { get; set; }
+    public long LeaderSkinId { get; set; }
+    public int DisplayOrder { get; set; }
+}

SVSim.Database/Models/ColosseumHofDeck.cs

@@ -0,0 +1,23 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Curated Hall-of-Fame deck pool for Arena Colosseum. Identical schema to
+/// <see cref="ColosseumWindFallDeck"/> and <see cref="ColosseumAvatarDeck"/> — separate
+/// tables instead of an enum-discriminated shared one because the operational lifecycle
+/// (per-pool importer, per-pool register endpoint, per-pool query) is independent.
+/// </summary>
+public class ColosseumHofDeck : IColosseumCuratedDeck
+{
+    public long Id { get; set; }
+    public int DeckNo { get; set; }
+    public int ClassId { get; set; }
+
+    [Column(TypeName = "jsonb")]
+    public string CardListJson { get; set; } = "[]";
+
+    public long SleeveId { get; set; }
+    public long LeaderSkinId { get; set; }
+    public int DisplayOrder { get; set; }
+}

SVSim.Database/Models/ColosseumWindFallDeck.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Curated WindFall (limited-pool wildcard) deck for Arena Colosseum. See
+/// <see cref="ColosseumHofDeck"/> for the rationale on the duplicated schema.
+/// </summary>
+public class ColosseumWindFallDeck : IColosseumCuratedDeck
+{
+    public long Id { get; set; }
+    public int DeckNo { get; set; }
+    public int ClassId { get; set; }
+
+    [Column(TypeName = "jsonb")]
+    public string CardListJson { get; set; } = "[]";
+
+    public long SleeveId { get; set; }
+    public long LeaderSkinId { get; set; }
+    public int DisplayOrder { get; set; }
+}

SVSim.Database/Models/IColosseumCuratedDeck.cs

@@ -0,0 +1,17 @@
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Common shape across the three curated-deck pool tables — used by the controller's
+/// generic list+register dispatcher (Phase 3 Task 10) to avoid duplicating identical code
+/// per pool. The interface is plumbing only; the pools stay distinct EF entity types.
+/// </summary>
+public interface IColosseumCuratedDeck
+{
+    long Id { get; set; }
+    int DeckNo { get; set; }
+    int ClassId { get; set; }
+    string CardListJson { get; set; }
+    long SleeveId { get; set; }
+    long LeaderSkinId { get; set; }
+    int DisplayOrder { get; set; }
+}