feat(tournament): implement hunting tournament system end-to-end

Wire format for MsgMhfEnterTournamentQuest (0x00D2) derived from
mhfo-hd.dll binary analysis (FUN_114f4280). Five new tables back
the full lifecycle: schedule, cups, sub-events, player registrations,
and run submissions. All six tournament handlers are now DB-driven:

- EnumerateRanking: returns active tournament schedule with cups and
  sub-events; computes phase state byte from timestamps
- EnumerateOrder: returns per-event leaderboard ranked by submission
  time, with SJIS-encoded character and guild names
- InfoTournament: exposes tournament detail and player registration
  state across all three query types
- EntryTournament: registers player and returns entry handle used by
  the client in the subsequent EnterTournamentQuest packet
- EnterTournamentQuest: parses the previously-unimplemented packet and
  records the run in tournament_results
- AcquireTournament: stubs rewards (item IDs not yet reversed)

Seed data (TournamentDefaults.sql) reproduces tournament #150 cups and
sub-events so a fresh install has a working tournament immediately.

server/migrations/seed/TournamentDefaults.sql

@@ -0,0 +1,62 @@
+-- Tournament #150 default data.
+-- One tournament is inserted that starts immediately and has a wide window so operators
+-- can adjust the timestamps after installation. The sub-events and cups are seeded
+-- idempotently via ON CONFLICT DO NOTHING.
+-- Cup groups: 16 = speed hunt (Brachydios variants), 17 = guild hunt, 6 = fishing size.
+-- Cup types: 7 = speed hunt, 6 = fishing size.
+
+BEGIN;
+
+-- Default tournament (always active on a fresh install).
+-- start_time = now, entry_end = +3 days, ranking_end = +13 days, reward_end = +20 days.
+INSERT INTO tournaments (name, start_time, entry_end, ranking_end, reward_end)
+SELECT
+    'Tournament #150',
+    EXTRACT(epoch FROM NOW())::bigint,
+    EXTRACT(epoch FROM NOW() + INTERVAL '3 days')::bigint,
+    EXTRACT(epoch FROM NOW() + INTERVAL '13 days')::bigint,
+    EXTRACT(epoch FROM NOW() + INTERVAL '20 days')::bigint
+WHERE NOT EXISTS (SELECT 1 FROM tournaments);
+
+-- Sub-events (shared across tournaments; NOT tournament-specific).
+-- CupGroup 16: Speed hunt Brachydios variants (event_sub_type 0-14, quest_file_id 60691).
+INSERT INTO tournament_sub_events (cup_group, event_sub_type, quest_file_id, name)
+SELECT * FROM (VALUES
+    (16::smallint,  0::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  1::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  2::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  3::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  4::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  5::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  6::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  7::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  8::smallint, 60691, 'ブラキディオス'),
+    (16::smallint,  9::smallint, 60691, 'ブラキディオス'),
+    (16::smallint, 10::smallint, 60691, 'ブラキディオス'),
+    (16::smallint, 11::smallint, 60691, 'ブラキディオス'),
+    (16::smallint, 12::smallint, 60691, 'ブラキディオス'),
+    (16::smallint, 13::smallint, 60691, 'ブラキディオス'),
+    (16::smallint, 14::smallint, 60691, 'ブラキディオス'),
+    -- CupGroup 17: Guild hunt Brachydios (event_sub_type -1)
+    (17::smallint, -1::smallint, 60690, 'ブラキディオスギルド'),
+    -- CupGroup 6: Fishing size categories
+    (6::smallint, 234::smallint, 0, 'キレアジ'),
+    (6::smallint, 237::smallint, 0, 'ハリマグロ'),
+    (6::smallint, 239::smallint, 0, 'カクサンデメキン')
+) AS v(cup_group, event_sub_type, quest_file_id, name)
+WHERE NOT EXISTS (SELECT 1 FROM tournament_sub_events);
+
+-- Cups for the default tournament.
+-- cup_type 7 = speed hunt, cup_type 6 = fishing size.
+INSERT INTO tournament_cups (tournament_id, cup_group, cup_type, unk, name, description)
+SELECT t.id, v.cup_group, v.cup_type, v.unk, v.name, v.description
+FROM tournaments t
+CROSS JOIN (VALUES
+    (16::smallint, 7::smallint, 0::smallint, 'スピードハントカップ',   'ブラキディオスをより速く狩れ'),
+    (17::smallint, 7::smallint, 0::smallint, 'ギルドハントカップ',     'ブラキディオスをギルドで狩れ'),
+    (6::smallint,  6::smallint, 0::smallint, 'フィッシングサイズカップ', '大きな魚を釣れ')
+) AS v(cup_group, cup_type, unk, name, description)
+WHERE NOT EXISTS (SELECT 1 FROM tournament_cups WHERE tournament_id = t.id)
+ORDER BY t.id;
+
+COMMIT;

server/migrations/sql/0015_tournament.sql

@@ -0,0 +1,48 @@
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS tournaments (
+    id          SERIAL PRIMARY KEY,
+    name        VARCHAR(64) NOT NULL,
+    start_time  BIGINT NOT NULL,
+    entry_end   BIGINT NOT NULL,
+    ranking_end BIGINT NOT NULL,
+    reward_end  BIGINT NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS tournament_cups (
+    id            SERIAL PRIMARY KEY,
+    tournament_id INTEGER NOT NULL REFERENCES tournaments(id) ON DELETE CASCADE,
+    cup_group     SMALLINT NOT NULL,
+    cup_type      SMALLINT NOT NULL,
+    unk           SMALLINT NOT NULL DEFAULT 0,
+    name          VARCHAR(64) NOT NULL,
+    description   TEXT NOT NULL DEFAULT ''
+);
+
+CREATE TABLE IF NOT EXISTS tournament_sub_events (
+    id             SERIAL PRIMARY KEY,
+    cup_group      SMALLINT NOT NULL,
+    event_sub_type SMALLINT NOT NULL DEFAULT 0,
+    quest_file_id  INTEGER NOT NULL DEFAULT 0,
+    name           VARCHAR(64) NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS tournament_entries (
+    id            SERIAL PRIMARY KEY,
+    char_id       INTEGER NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
+    tournament_id INTEGER NOT NULL REFERENCES tournaments(id) ON DELETE CASCADE,
+    registered_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (char_id, tournament_id)
+);
+
+CREATE TABLE IF NOT EXISTS tournament_results (
+    id            SERIAL PRIMARY KEY,
+    char_id       INTEGER NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
+    tournament_id INTEGER NOT NULL REFERENCES tournaments(id) ON DELETE CASCADE,
+    event_id      INTEGER NOT NULL,
+    quest_slot    INTEGER NOT NULL DEFAULT 0,
+    stage_handle  INTEGER NOT NULL DEFAULT 0,
+    submitted_at  TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+COMMIT;