Add backend foundation and config-driven workbench

backend/internal/store/postgres/entry_store.go

@@ -0,0 +1,74 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgx/v5"
+)
+
+type EntryChannel struct {
+	ID            string
+	ChannelCode   string
+	ChannelType   string
+	PlatformAppID *string
+	DisplayName   string
+	Status        string
+	IsDefault     bool
+	TenantID      string
+	TenantCode    string
+	TenantName    string
+}
+
+type FindEntryChannelParams struct {
+	ChannelCode   string
+	ChannelType   string
+	PlatformAppID string
+	TenantCode    string
+}
+
+func (s *Store) FindEntryChannel(ctx context.Context, params FindEntryChannelParams) (*EntryChannel, error) {
+	row := s.pool.QueryRow(ctx, `
+		SELECT
+			ec.id,
+			ec.channel_code,
+			ec.channel_type,
+			ec.platform_app_id,
+			ec.display_name,
+			ec.status,
+			ec.is_default,
+			t.id,
+			t.tenant_code,
+			t.name
+		FROM entry_channels ec
+		JOIN tenants t ON t.id = ec.tenant_id
+		WHERE ($1 = '' OR ec.channel_code = $1)
+		  AND ($2 = '' OR ec.channel_type = $2)
+		  AND ($3 = '' OR COALESCE(ec.platform_app_id, '') = $3)
+		  AND ($4 = '' OR t.tenant_code = $4)
+		ORDER BY ec.is_default DESC, ec.created_at ASC
+		LIMIT 1
+	`, params.ChannelCode, params.ChannelType, params.PlatformAppID, params.TenantCode)
+
+	var entry EntryChannel
+	err := row.Scan(
+		&entry.ID,
+		&entry.ChannelCode,
+		&entry.ChannelType,
+		&entry.PlatformAppID,
+		&entry.DisplayName,
+		&entry.Status,
+		&entry.IsDefault,
+		&entry.TenantID,
+		&entry.TenantCode,
+		&entry.TenantName,
+	)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("find entry channel: %w", err)
+	}
+	return &entry, nil
+}