refactor: привести кодовую базу в соответствие с канонами bible

- 400 → 422 для всех ошибок валидации входных данных (handlers: export, quote, sync, vendor_spec, partnumber_books, pricelist)
- SQL-запросы вынесены из handlers в localdb (partnumber_books, pricelist, support_bundle); ValidateMariaDBConnection перенесён в internal/db/validate.go
- List-ответы унифицированы: ключ items, поля total_count/page/per_page/total_pages (component, pricelist, partnumber_books); шаблоны обновлены
- Молчаливые ошибки заменены на slog.Warn/Error (support_bundle, vendor_spec, component, configuration, local_configuration, localdb)
- N+1 запросы устранены: batch-запросы в export.go и vendor_workspace_import.go
- fmt.Println → slog в cmd/ (qfs, migrate, migrate_ops_projects, migrate_project_updated_at)
- Заголовки recovery/verify добавлены во все 28 SQL-миграций
- Добавлены bible-local/runtime-flows.md и bible-local/decisions/
- Обновлён субмодуль bible до v0.2.0-13

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/db/validate.go

@@ -0,0 +1,60 @@
+package db
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	gormmysql "gorm.io/driver/mysql"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+var errPermissionProbeRollback = errors.New("permission probe rollback")
+
+// ValidateMariaDBConnection opens a one-off connection using dsn, pings, checks
+// the required lot table exists, and probes write access to qt_client_schema_state.
+// Returns (lot row count, canWrite, error).
+func ValidateMariaDBConnection(dsn string) (int64, bool, error) {
+	db, err := gorm.Open(gormmysql.Open(dsn), &gorm.Config{
+		Logger: logger.Default.LogMode(logger.Silent),
+	})
+	if err != nil {
+		return 0, false, fmt.Errorf("open MariaDB connection: %w", err)
+	}
+
+	sqlDB, err := db.DB()
+	if err != nil {
+		return 0, false, fmt.Errorf("get database handle: %w", err)
+	}
+	defer sqlDB.Close()
+
+	if err := sqlDB.Ping(); err != nil {
+		return 0, false, fmt.Errorf("ping MariaDB: %w", err)
+	}
+
+	var lotCount int64
+	if err := db.Table("lot").Count(&lotCount).Error; err != nil {
+		return 0, false, fmt.Errorf("check required table lot: %w", err)
+	}
+
+	return lotCount, testSyncWritePermission(db), nil
+}
+
+func testSyncWritePermission(db *gorm.DB) bool {
+	sentinel := fmt.Sprintf("quoteforge-permission-check-%d", time.Now().UnixNano())
+	err := db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Exec(`
+			INSERT INTO qt_client_schema_state (username, hostname, last_checked_at, updated_at)
+			VALUES (?, ?, NOW(), NOW())
+			ON DUPLICATE KEY UPDATE
+				last_checked_at = VALUES(last_checked_at),
+				updated_at = VALUES(updated_at)
+		`, sentinel, "setup-check").Error; err != nil {
+			return err
+		}
+		return errPermissionProbeRollback
+	})
+
+	return errors.Is(err, errPermissionProbeRollback)
+}