refactor(channelserver): extract Event, Achievement, Shop, and Cafe repositories

Move 22 raw SQL queries from 4 handler files into dedicated repository
structs, continuing the repository extraction pattern. Achievement
insert uses ON CONFLICT DO NOTHING to eliminate check-then-insert race,
and IncrementScore validates the column index to prevent SQL injection.

server/channelserver/repo_cafe.go

@@ -0,0 +1,61 @@
+package channelserver
+
+import (
+	"github.com/jmoiron/sqlx"
+)
+
+// CafeRepository centralizes all database access for cafe-related tables.
+type CafeRepository struct {
+	db *sqlx.DB
+}
+
+// NewCafeRepository creates a new CafeRepository.
+func NewCafeRepository(db *sqlx.DB) *CafeRepository {
+	return &CafeRepository{db: db}
+}
+
+// ResetAccepted deletes all accepted cafe bonuses for a character.
+func (r *CafeRepository) ResetAccepted(charID uint32) error {
+	_, err := r.db.Exec(`DELETE FROM cafe_accepted WHERE character_id=$1`, charID)
+	return err
+}
+
+// GetBonuses returns all cafe bonuses with their claimed status for a character.
+func (r *CafeRepository) GetBonuses(charID uint32) (*sqlx.Rows, error) {
+	return r.db.Queryx(`
+	SELECT cb.id, time_req, item_type, item_id, quantity,
+	(
+		SELECT count(*)
+		FROM cafe_accepted ca
+		WHERE cb.id = ca.cafe_id AND ca.character_id = $1
+	)::int::bool AS claimed
+	FROM cafebonus cb ORDER BY id ASC;`, charID)
+}
+
+// GetClaimable returns unclaimed cafe bonuses where the character has enough accumulated time.
+func (r *CafeRepository) GetClaimable(charID uint32, elapsedSec int64) (*sqlx.Rows, error) {
+	return r.db.Queryx(`
+	SELECT c.id, time_req, item_type, item_id, quantity
+	FROM cafebonus c
+	WHERE (
+		SELECT count(*)
+		FROM cafe_accepted ca
+		WHERE c.id = ca.cafe_id AND ca.character_id = $1
+	) < 1 AND (
+		SELECT ch.cafe_time + $2
+		FROM characters ch
+		WHERE ch.id = $1
+	) >= time_req`, charID, elapsedSec)
+}
+
+// GetBonusItem returns the item type and quantity for a specific cafe bonus.
+func (r *CafeRepository) GetBonusItem(bonusID uint32) (itemType, quantity uint32, err error) {
+	err = r.db.QueryRow(`SELECT cb.id, item_type, quantity FROM cafebonus cb WHERE cb.id=$1`, bonusID).Scan(&bonusID, &itemType, &quantity)
+	return
+}
+
+// AcceptBonus records that a character has accepted a cafe bonus.
+func (r *CafeRepository) AcceptBonus(bonusID, charID uint32) error {
+	_, err := r.db.Exec("INSERT INTO cafe_accepted VALUES ($1, $2)", bonusID, charID)
+	return err
+}