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/channelserver/test_helpers_test.go

@@ -48,9 +48,10 @@ func createMockServer() *Server {
 			state:    make([]uint32, 30),
 			support:  make([]uint32, 30),
 		},
-		// divaRepo default prevents nil-deref in diva handler tests that don't
-		// need specific repo behaviour. Tests that need controlled data override it.
-		divaRepo: &mockDivaRepo{},
+		// divaRepo and tournamentRepo defaults prevent nil-deref in handler tests
+		// that don't need specific repo behaviour. Tests that need controlled data override them.
+		divaRepo:       &mockDivaRepo{},
+		tournamentRepo: &mockTournamentRepo{},
 	}
 	s.i18n = getLangStrings(s)
 	s.Registry = NewLocalChannelRegistry([]*Server{s})