feat(diva): implement Diva Defense (UD) system

Add full Diva Defense / United Defense system: schema, repo layer,
i18n bead names, and RE-verified packet handler implementations.

Schema (0011_diva.sql): diva_beads, diva_beads_assignment,
diva_beads_points, diva_prizes tables; interception_maps/points
columns on guilds and guild_characters.

Seed (DivaDefaults.sql): 26 prize milestones for personal and
guild reward tracks (item_type=26 diva coins).

Repo (DivaRepo): 11 new methods covering bead assignment, point
accumulation, interception point tracking, prize queries, and
cleanup. Mocks wired in test_helpers_test.go.

i18n: Bead struct with EN/JP names for all 18 bead types (IDs
1–25). Session tracks currentBeadIndex (-1 = none assigned).

Packet handlers corrected against mhfo-hd.dll RE findings:
- GetKijuInfo: u8 count, 512-byte desc, color_id+bead_type per entry
- SetKiju: 1-byte ACK; persists bead assignment to DB
- GetUdMyPoint: 8×18-byte entries, no count prefix
- GetUdTotalPointInfo: u8 error + u64[64] + u8[64] + u64 (~585 B)
- GetUdSelectedColorInfo: u8 error + u8[8] = 9 bytes
- GetUdDailyPresentList: correct u16 count format (was wrong hex)
- GetUdNormaPresentList: correct u16 count format (was wrong hex)
- GetUdRankingRewardList: correct u16 count with u32 item_id/qty
- GetRewardSong: 22-byte layout with 0xFFFFFFFF prayer_end sentinel
- AddRewardSongCount: parse implemented (was NOT IMPLEMENTED stub)

server/channelserver/repo_interfaces.go

@@ -322,6 +322,18 @@ type GoocooRepo interface {
 	SaveSlot(charID uint32, slot uint32, data []byte) error
 }
 
+// DivaPrize represents a single reward milestone for the personal or guild track.
+type DivaPrize struct {
+	ID         int
+	Type       string
+	PointsReq  int
+	ItemType   int
+	ItemID     int
+	Quantity   int
+	GR         bool
+	Repeatable bool
+}
+
 // DivaRepo defines the contract for diva event data access.
 type DivaRepo interface {
 	DeleteEvents() error
@@ -330,6 +342,23 @@ type DivaRepo interface {
 	AddPoints(charID uint32, eventID uint32, questPoints, bonusPoints uint32) error
 	GetPoints(charID uint32, eventID uint32) (questPoints, bonusPoints int64, err error)
 	GetTotalPoints(eventID uint32) (questPoints, bonusPoints int64, err error)
+
+	// Bead management
+	GetBeads() ([]int, error)
+	AssignBead(characterID uint32, beadIndex int, expiry time.Time) error
+	AddBeadPoints(characterID uint32, beadIndex int, points int) error
+	GetCharacterBeadPoints(characterID uint32) (map[int]int, error)
+	GetTotalBeadPoints() (int64, error)
+	GetTopBeadPerDay(day int) (int, error)
+	CleanupBeads() error
+
+	// Prize rewards
+	GetPersonalPrizes() ([]DivaPrize, error)
+	GetGuildPrizes() ([]DivaPrize, error)
+
+	// Interception points (guild_characters.interception_points JSON)
+	GetCharacterInterceptionPoints(characterID uint32) (map[string]int, error)
+	AddInterceptionPoints(characterID uint32, questFileID int, points int) error
 }
 
 // MiscRepo defines the contract for miscellaneous data access.