feat(backup): take Tinyforge DB snapshot before every deploy

Adds an opt-in "auto_backup_before_deploy" setting that triggers a
"pre-deploy" backup at the start of every project deploy via the deploy
pipeline (covers both the async HTTP path and the sync poller/webhook
path). Failures are logged to the deploy log but do not abort — missing
a backup is preferable to refusing to ship a fix.

- store: settings.auto_backup_before_deploy column + scan/update wiring
- backup: accept "pre-deploy" as a valid backup_type
- deployer: small PreDeployBackuper interface, hooked into runDeploy
  right after settings load and before any state-mutating work
- api: settings request/response surface the new flag
- web: ToggleSwitch on the backup settings page; "Pre-deploy" badge
  variant in the backup list (badge-warning so it stands out)
- i18n: en/ru strings for the toggle, help text, and badge label

internal/store/models.go

@@ -82,6 +82,10 @@ type Settings struct {
 	BackupEnabled       bool   `json:"backup_enabled"`
 	BackupIntervalHours  int    `json:"backup_interval_hours"`
 	BackupRetentionCount int    `json:"backup_retention_count"`
+	// AutoBackupBeforeDeploy creates a "pre-deploy" Tinyforge DB backup
+	// at the start of every project deploy. Independent of BackupEnabled
+	// (which governs the periodic auto-backup cron).
+	AutoBackupBeforeDeploy bool `json:"auto_backup_before_deploy"`
 	StatsIntervalSeconds int    `json:"stats_interval_seconds"` // 0 disables collection
 	StatsRetentionHours  int    `json:"stats_retention_hours"`  // 0 disables collection
 	UpdatedAt            string `json:"updated_at"`