refactor(channelserver): eliminate *sqlx.Rows/*sql.Rows from repository interfaces

Move scan loops from handlers into repository methods so that interfaces
return typed slices instead of leaking database cursors. This fixes
resource leaks (7 of 12 call sites never closed rows) and makes all
12 methods mockable for unit tests.

Affected repos: CafeRepo, ShopRepo, EventRepo, RengokuRepo, DivaRepo,
ScenarioRepo, MiscRepo, MercenaryRepo. New structs: DivaEvent,
MercenaryLoan, GuildHuntCatUsage. EventRepo.GetEventQuests left as-is
(requires broader Server refactor).

server/channelserver/repo_mercenary.go

@@ -1,7 +1,8 @@
 package channelserver
 
 import (
-	"database/sql"
+	"fmt"
+	"time"
 
 	"github.com/jmoiron/sqlx"
 )
@@ -30,21 +31,73 @@ func (r *MercenaryRepository) NextAirouID() (uint32, error) {
 	return id, err
 }
 
+// MercenaryLoan represents a character that has a pact with a rasta.
+type MercenaryLoan struct {
+	Name   string
+	CharID uint32
+	PactID int
+}
+
 // GetMercenaryLoans returns characters that have a pact with the given character's rasta_id.
-func (r *MercenaryRepository) GetMercenaryLoans(charID uint32) (*sql.Rows, error) {
-	return r.db.Query("SELECT name, id, pact_id FROM characters WHERE pact_id=(SELECT rasta_id FROM characters WHERE id=$1)", charID)
+func (r *MercenaryRepository) GetMercenaryLoans(charID uint32) ([]MercenaryLoan, error) {
+	rows, err := r.db.Query("SELECT name, id, pact_id FROM characters WHERE pact_id=(SELECT rasta_id FROM characters WHERE id=$1)", charID)
+	if err != nil {
+		return nil, fmt.Errorf("query mercenary loans: %w", err)
+	}
+	defer rows.Close()
+	var result []MercenaryLoan
+	for rows.Next() {
+		var l MercenaryLoan
+		if err := rows.Scan(&l.Name, &l.CharID, &l.PactID); err != nil {
+			return nil, fmt.Errorf("scan mercenary loan: %w", err)
+		}
+		result = append(result, l)
+	}
+	return result, rows.Err()
+}
+
+// GuildHuntCatUsage represents cats_used and start time from a guild hunt.
+type GuildHuntCatUsage struct {
+	CatsUsed string
+	Start    time.Time
 }
 
 // GetGuildHuntCatsUsed returns cats_used and start from guild_hunts for a given character.
-func (r *MercenaryRepository) GetGuildHuntCatsUsed(charID uint32) (*sql.Rows, error) {
-	return r.db.Query(`SELECT cats_used, start FROM guild_hunts gh
+func (r *MercenaryRepository) GetGuildHuntCatsUsed(charID uint32) ([]GuildHuntCatUsage, error) {
+	rows, err := r.db.Query(`SELECT cats_used, start FROM guild_hunts gh
 		INNER JOIN characters c ON gh.host_id = c.id WHERE c.id=$1`, charID)
+	if err != nil {
+		return nil, fmt.Errorf("query guild hunt cats: %w", err)
+	}
+	defer rows.Close()
+	var result []GuildHuntCatUsage
+	for rows.Next() {
+		var u GuildHuntCatUsage
+		if err := rows.Scan(&u.CatsUsed, &u.Start); err != nil {
+			return nil, fmt.Errorf("scan guild hunt cat: %w", err)
+		}
+		result = append(result, u)
+	}
+	return result, rows.Err()
 }
 
 // GetGuildAirou returns otomoairou data for all characters in a guild.
-func (r *MercenaryRepository) GetGuildAirou(guildID uint32) (*sql.Rows, error) {
-	return r.db.Query(`SELECT c.otomoairou FROM characters c
+func (r *MercenaryRepository) GetGuildAirou(guildID uint32) ([][]byte, error) {
+	rows, err := r.db.Query(`SELECT c.otomoairou FROM characters c
 	INNER JOIN guild_characters gc ON gc.character_id = c.id
 	WHERE gc.guild_id = $1 AND c.otomoairou IS NOT NULL
 	ORDER BY c.id LIMIT 60`, guildID)
+	if err != nil {
+		return nil, fmt.Errorf("query guild airou: %w", err)
+	}
+	defer rows.Close()
+	var result [][]byte
+	for rows.Next() {
+		var data []byte
+		if err := rows.Scan(&data); err != nil {
+			return nil, fmt.Errorf("scan guild airou: %w", err)
+		}
+		result = append(result, data)
+	}
+	return result, rows.Err()
 }