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_scenario.go

@@ -0,0 +1,20 @@
+package channelserver
+
+import (
+	"github.com/jmoiron/sqlx"
+)
+
+// ScenarioRepository centralizes all database access for the scenario_counter table.
+type ScenarioRepository struct {
+	db *sqlx.DB
+}
+
+// NewScenarioRepository creates a new ScenarioRepository.
+func NewScenarioRepository(db *sqlx.DB) *ScenarioRepository {
+	return &ScenarioRepository{db: db}
+}
+
+// GetCounters returns all scenario counters.
+func (r *ScenarioRepository) GetCounters() (*sqlx.Rows, error) {
+	return r.db.Queryx("SELECT scenario_id, category_id FROM scenario_counter")
+}