refactor(channelserver): extract Goocoo, Diva, Misc, Scenario, and Mercenary repositories

Move remaining raw s.server.db.* queries from handler files into
dedicated repository structs, completing the repository extraction
effort. Also adds SaveCharacterData and SaveHouseData to
CharacterRepository.

Fixes guild_hunts query to select both cats_used and start columns
to match the existing two-column Scan call. Adds slot index
validation in GoocooRepository to prevent SQL injection via
fmt.Sprintf.

server/channelserver/repo_diva.go

@@ -0,0 +1,32 @@
+package channelserver
+
+import (
+	"github.com/jmoiron/sqlx"
+)
+
+// DivaRepository centralizes all database access for diva defense events.
+type DivaRepository struct {
+	db *sqlx.DB
+}
+
+// NewDivaRepository creates a new DivaRepository.
+func NewDivaRepository(db *sqlx.DB) *DivaRepository {
+	return &DivaRepository{db: db}
+}
+
+// DeleteEvents removes all diva events.
+func (r *DivaRepository) DeleteEvents() error {
+	_, err := r.db.Exec("DELETE FROM events WHERE event_type='diva'")
+	return err
+}
+
+// InsertEvent creates a new diva event with the given start epoch.
+func (r *DivaRepository) InsertEvent(startEpoch uint32) error {
+	_, err := r.db.Exec("INSERT INTO events (event_type, start_time) VALUES ('diva', to_timestamp($1)::timestamp without time zone)", startEpoch)
+	return err
+}
+
+// GetEvents returns all diva events with their ID and start_time epoch.
+func (r *DivaRepository) GetEvents() (*sqlx.Rows, error) {
+	return r.db.Queryx("SELECT id, (EXTRACT(epoch FROM start_time)::int) as start_time FROM events WHERE event_type='diva'")
+}