feat(arena-colosseum): lobby + constructed entry (phase 1)

Closes 5 of arena-colosseum's 16 spec shapes (1/16 → 6/16). Lobby reads
(/top, /get_fee_info, /event_info) render an empty "no event scheduled"
payload by default; /entry + /register_deck activate via admin-flipped
ColosseumSeason + ColosseumRounds config sections.

* Schema: ViewerArenaColosseumRun standalone table (unique on ViewerId)
  with jsonb run-state columns mirroring ViewerArenaTwoPickRun.
* Config sections: ColosseumSeasonConfig (event-level), ColosseumRoundsConfig
  (the 3-round bracket). Empty defaults — IsColosseumPeriod=false.
* Migration AddArenaColosseumRun (DDL only; seed rows come from the section
  ShippedDefaults via EnsureSeedDataAsync).
* DTOs: ColosseumLobbyInfo (round-level, /top + /get_fee_info), ColosseumEventInfo
  (event-level, /event_info), ColosseumOwnStatus (shared status block),
  ColosseumEntryRef, ColosseumFeeList, ColosseumUserDeck, ColosseumBattleResults,
  ColosseumRoundDetail + ColosseumGroupRow. EventInfoResponse uses explicit
  [JsonPropertyName("1"|"2"|"3")] for the string-keyed rounds shape per spec.
* Controller: ArenaColosseumController replaces the 1-action stub with
  the five lifecycle endpoints. /top emits leader_skin_id even when 0
  (project_wire_null_policy override).
* Tests: 11 controller-level tests + 6 config round-trip tests covering
  empty-season payloads, run-seeded /top round-trip, crystal/rupy entry
  debits, now_round_id mismatch rejection, deck_no_list round-trip + reject.

SVSim.Database/Models/Config/ColosseumRoundsConfig.cs

@@ -0,0 +1,47 @@
+namespace SVSim.Database.Models.Config;
+
+/// <summary>
+/// The 3-round bracket schedule for an active Colosseum season. Empty <see cref="Rounds"/>
+/// is the default shipped state — lobby <c>/event_info</c> renders a benign payload with
+/// no rounds active. Collection default is in <see cref="ShippedDefaults"/> per
+/// feedback_config_defaults (property-initializer collection defaults silently empty out
+/// under the tier merge).
+/// </summary>
+[ConfigSection("ColosseumRounds")]
+public class ColosseumRoundsConfig
+{
+    public List<RoundEntry> Rounds { get; set; } = new();
+
+    public static ColosseumRoundsConfig ShippedDefaults() => new()
+    {
+        Rounds = new(),
+    };
+
+    public class RoundEntry
+    {
+        /// <summary>1, 2, or 3 in the canonical 3-round schedule.</summary>
+        public int RoundId { get; set; }
+
+        public DateTime StartTime { get; set; }
+        public DateTime EndTime { get; set; }
+
+        /// <summary>Bracket groups within the round (e.g. distinct breakthrough thresholds
+        /// for late-joiners). The first entry is the canonical lookup used by
+        /// <c>ColosseumProgressionService</c> for the v1 single-bracket case.</summary>
+        public List<GroupEntry> Groups { get; set; } = new();
+    }
+
+    public class GroupEntry
+    {
+        public string Group { get; set; } = "";
+
+        /// <summary>Max battles a viewer can play in this round before bracket termination.</summary>
+        public int MaxBattleCount { get; set; }
+
+        /// <summary>Wins required to promote out of this round.</summary>
+        public int BreakthroughNumber { get; set; }
+
+        /// <summary>Total bracket entries allotted to this group.</summary>
+        public int EntryNumber { get; set; }
+    }
+}

SVSim.Database/Models/Config/ColosseumSeasonConfig.cs

@@ -0,0 +1,68 @@
+using SVSim.Database.Enums;
+
+namespace SVSim.Database.Models.Config;
+
+/// <summary>
+/// Event-level configuration for an active Arena Colosseum (Grand Prix) season. Default
+/// <see cref="ShippedDefaults"/> emits <c>IsColosseumPeriod = false</c> so the lobby read
+/// endpoints render an empty "no event scheduled" payload without crashing the client.
+/// Flipping the event on is an admin operation per
+/// <c>docs/operations/grand-prix-event-setup.md</c> — write a row to <c>GameConfigs</c>.
+/// </summary>
+[ConfigSection("ColosseumSeason")]
+public class ColosseumSeasonConfig
+{
+    /// <summary>Master gate. <c>false</c> = lobby reads render an empty info block and
+    /// entry rejects. The client (<c>Wizard/ColosseumEntryInfoTask.cs</c>) reads this and
+    /// skips parsing the rest of the colosseum_info object.</summary>
+    public bool IsColosseumPeriod { get; set; }
+
+    /// <summary>Stamped onto every <see cref="ViewerArenaColosseumRun"/> at entry time.</summary>
+    public int SeasonId { get; set; }
+
+    public string ColosseumName { get; set; } = "";
+
+    /// <summary>Bracket format. Stamped onto the run at entry time.</summary>
+    public Format DeckFormat { get; set; } = Format.Rotation;
+
+    /// <summary>Server stores bool; the wire shape is the STRING "0"/"1" per Wizard/ColosseumEntryInfoTask.cs's
+    /// <c>jsonData.ToString() == "1"</c> parse. The response DTO converts at serialization time.</summary>
+    public bool IsNormalTwoPick { get; set; }
+
+    /// <summary>Wire string used by the client as a theme/color code. Empty when not in special mode.</summary>
+    public string IsSpecialMode { get; set; } = "";
+
+    public string? AnnounceId { get; set; }
+
+    public DateTime EventStartTime { get; set; }
+    public DateTime EventEndTime { get; set; }
+
+    /// <summary>How many bracket entries get eliminated in the final round before champion-determination.</summary>
+    public int FinalRoundEliminateCount { get; set; }
+
+    public string CardPoolName { get; set; } = "";
+
+    /// <summary>Card-set ids used as the 2-Pick / Chaos draft pool override for this season.
+    /// Phase 3 reads this through <c>ArenaTwoPickCardPoolService</c> instead of
+    /// <c>ChallengeConfig.PoolCardSetIds</c>.</summary>
+    public List<int> PoolCardSetIds { get; set; } = new();
+
+    public int RupyCost { get; set; }
+    public int TicketCost { get; set; }
+    public int CrystalCost { get; set; }
+
+    public bool IsAllowedFreeEntry { get; set; }
+
+    public bool IsAllCardEnabled { get; set; }
+
+    /// <summary>Number of strategies offered per pick in 2-Pick Chaos mode.</summary>
+    public int StrategyPickNum { get; set; }
+
+    public DateTime SalesPeriodStart { get; set; }
+    public DateTime SalesPeriodEnd { get; set; }
+
+    public static ColosseumSeasonConfig ShippedDefaults() => new()
+    {
+        IsColosseumPeriod = false,
+    };
+}

SVSim.Database/Models/ViewerArenaColosseumRun.cs

@@ -0,0 +1,105 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+using SVSim.Database.Enums;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One active Grand Prix (Arena Colosseum) bracket run per viewer. Mirrors
+/// <see cref="ViewerArenaTwoPickRun"/> in shape so the 2-Pick draft state machine can be
+/// lifted onto it in Phase 3 — the schema is the union of constructed-mode lifecycle
+/// (registered decks, bracket counts, rank-match promotion flag) and TK2-style draft
+/// state. Standalone (not a Viewer owned collection) per
+/// project_ef_nav_include_pitfall, with a unique index on ViewerId to enforce
+/// "one active run per viewer". Row is deleted on /finish or /retire.
+/// </summary>
+[Index(nameof(ViewerId), IsUnique = true)]
+public class ViewerArenaColosseumRun
+{
+    public long Id { get; set; }
+
+    public long ViewerId { get; set; }
+
+    /// <summary>Wire <c>entry_info.id</c>. Set to <see cref="Id"/> on insert.</summary>
+    public long EntryId { get; set; }
+
+    /// <summary>Stamped from <see cref="Config.ColosseumSeasonConfig.SeasonId"/> at entry time so
+    /// mid-run season-config edits don't shift the run's identity.</summary>
+    public int SeasonId { get; set; }
+
+    /// <summary>Current bracket round (1..3 in the canonical 3-round schedule). Indexes
+    /// <see cref="Config.ColosseumRoundsConfig.Rounds"/> at entry time, advances on bracket
+    /// promotion via <c>ColosseumProgressionService</c>.</summary>
+    public int RoundId { get; set; }
+
+    /// <summary>Format the bracket plays in (Rotation/Unlimited/TwoPick/HOF/WindFall/Avatar/...).
+    /// Stamped from season config at entry time.</summary>
+    public Format DeckFormat { get; set; }
+
+    public long LeaderSkinId { get; set; }
+
+    /// <summary>eARENA_PAY: 1 = ticket, 2 = crystal, 3 = rupy, 0 = free entry. Stamped at entry.</summary>
+    public int ConsumeItemType { get; set; }
+
+    // --- 2-Pick / Chaos draft state (lifted from ViewerArenaTwoPickRun for Phase 3) ---
+
+    [Column(TypeName = "jsonb")]
+    public string CandidateClassIdsJson { get; set; } = "[]";
+
+    /// <summary>Stored as 0 in constructed mode (no draft turn machinery).</summary>
+    public int SelectTurn { get; set; }
+
+    public bool IsSelectCompleted { get; set; }
+
+    [Column(TypeName = "jsonb")]
+    public string SelectedCardIdsJson { get; set; } = "[]";
+
+    [Column(TypeName = "jsonb")]
+    public string PendingPickSetsJson { get; set; } = "[]";
+
+    /// <summary>Monotonic counter for CandidatePair.Id; advances by 2 each draft turn.</summary>
+    public long NextCandidateId { get; set; } = 1;
+
+    /// <summary>Selected class for 2-Pick / Chaos modes; 0 in constructed mode.</summary>
+    public int ClassId { get; set; }
+
+    /// <summary>Optional Chaos sub-mode replay id. 0 when not in Chaos.</summary>
+    public int ChaosId { get; set; }
+
+    // --- Per-round bracket state ---
+
+    [Column(TypeName = "jsonb")]
+    public string ResultListJson { get; set; } = "[]";
+
+    public int WinCount { get; set; }
+    public int LossCount { get; set; }
+    public int BattleCountThisRound { get; set; }
+
+    /// <summary>Cap copied from the matching <c>ColosseumRoundsConfig.Rounds[RoundId-1].Groups[0]</c>
+    /// at entry — stamped so mid-run round-config edits don't shift the cap.</summary>
+    public int MaxBattleCountThisRound { get; set; }
+
+    /// <summary>Wins required to break through to the next round. Same stamping rule as
+    /// <see cref="MaxBattleCountThisRound"/>.</summary>
+    public int BreakthroughNumberThisRound { get; set; }
+
+    /// <summary>Remaining attempts in the current entry. Decremented per battle finish until
+    /// 0 or breakthrough.</summary>
+    public int RestEntryNum { get; set; }
+
+    /// <summary>Flipped exactly once when the node signals <c>matching_state == 3008</c>.
+    /// Subsequent battle URLs use the <c>colosseum_rank_battle/*</c> prefix.</summary>
+    public bool IsRankMatching { get; set; }
+
+    public bool IsChampion { get; set; }
+
+    // --- Registered deck slot (constructed mode) ---
+
+    [Column(TypeName = "jsonb")]
+    public string RegisteredDeckNoListJson { get; set; } = "[]";
+
+    public bool IsPublished { get; set; }
+
+    public DateTime CreatedAt { get; set; }
+    public DateTime UpdatedAt { get; set; }
+}