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_goocoo.go

@@ -0,0 +1,59 @@
+package channelserver
+
+import (
+	"fmt"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// GoocooRepository centralizes all database access for the goocoo table.
+type GoocooRepository struct {
+	db *sqlx.DB
+}
+
+// NewGoocooRepository creates a new GoocooRepository.
+func NewGoocooRepository(db *sqlx.DB) *GoocooRepository {
+	return &GoocooRepository{db: db}
+}
+
+// validGoocooSlot validates the slot index to prevent SQL injection.
+func validGoocooSlot(slot uint32) error {
+	if slot > 4 {
+		return fmt.Errorf("invalid goocoo slot index: %d", slot)
+	}
+	return nil
+}
+
+// EnsureExists creates a goocoo record if it doesn't already exist.
+func (r *GoocooRepository) EnsureExists(charID uint32) error {
+	_, err := r.db.Exec("INSERT INTO goocoo (id) VALUES ($1) ON CONFLICT DO NOTHING", charID)
+	return err
+}
+
+// GetSlot reads a single goocoo slot by character ID and slot index (0-4).
+func (r *GoocooRepository) GetSlot(charID uint32, slot uint32) ([]byte, error) {
+	if err := validGoocooSlot(slot); err != nil {
+		return nil, err
+	}
+	var data []byte
+	err := r.db.QueryRow(fmt.Sprintf("SELECT goocoo%d FROM goocoo WHERE id=$1", slot), charID).Scan(&data)
+	return data, err
+}
+
+// ClearSlot sets a goocoo slot to NULL.
+func (r *GoocooRepository) ClearSlot(charID uint32, slot uint32) error {
+	if err := validGoocooSlot(slot); err != nil {
+		return err
+	}
+	_, err := r.db.Exec(fmt.Sprintf("UPDATE goocoo SET goocoo%d=NULL WHERE id=$1", slot), charID)
+	return err
+}
+
+// SaveSlot writes data to a goocoo slot.
+func (r *GoocooRepository) SaveSlot(charID uint32, slot uint32, data []byte) error {
+	if err := validGoocooSlot(slot); err != nil {
+		return err
+	}
+	_, err := r.db.Exec(fmt.Sprintf("UPDATE goocoo SET goocoo%d=$1 WHERE id=$2", slot), data, charID)
+	return err
+}