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_event.go

@@ -0,0 +1,47 @@
+package channelserver
+
+import (
+	"time"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// EventRepository centralizes all database access for event-related tables.
+type EventRepository struct {
+	db *sqlx.DB
+}
+
+// NewEventRepository creates a new EventRepository.
+func NewEventRepository(db *sqlx.DB) *EventRepository {
+	return &EventRepository{db: db}
+}
+
+// GetFeatureWeapon returns the featured weapon bitfield for a given start time.
+func (r *EventRepository) GetFeatureWeapon(startTime time.Time) (activeFeature, error) {
+	var af activeFeature
+	err := r.db.QueryRowx(`SELECT start_time, featured FROM feature_weapon WHERE start_time=$1`, startTime).StructScan(&af)
+	return af, err
+}
+
+// InsertFeatureWeapon stores a new featured weapon entry.
+func (r *EventRepository) InsertFeatureWeapon(startTime time.Time, features uint32) error {
+	_, err := r.db.Exec(`INSERT INTO feature_weapon VALUES ($1, $2)`, startTime, features)
+	return err
+}
+
+// GetLoginBoosts returns all login boost rows for a character, ordered by week_req.
+func (r *EventRepository) GetLoginBoosts(charID uint32) (*sqlx.Rows, error) {
+	return r.db.Queryx("SELECT week_req, expiration, reset FROM login_boost WHERE char_id=$1 ORDER BY week_req", charID)
+}
+
+// InsertLoginBoost creates a new login boost entry.
+func (r *EventRepository) InsertLoginBoost(charID uint32, weekReq uint8, expiration, reset time.Time) error {
+	_, err := r.db.Exec(`INSERT INTO login_boost VALUES ($1, $2, $3, $4)`, charID, weekReq, expiration, reset)
+	return err
+}
+
+// UpdateLoginBoost updates expiration and reset for a login boost entry.
+func (r *EventRepository) UpdateLoginBoost(charID uint32, weekReq uint8, expiration, reset time.Time) error {
+	_, err := r.db.Exec(`UPDATE login_boost SET expiration=$1, reset=$2 WHERE char_id=$3 AND week_req=$4`, expiration, reset, charID, weekReq)
+	return err
+}