Root cause: saveJob() used stale sourceDatasourceId (set once on load)
instead of live datasourceId (updated by ConfigTabForm via $bindable).
Since sourceDatasourceId was always truthy, the || fallback to datasourceId
never triggered — the old datasource ID was always sent to PUT.
Fixes:
- Removed dead sourceDatasourceId atom; saveJob() uses datasourceId directly
- Bound sourceTable via $bindable through ConfigTabForm; updated on select
- loadDatasourceColumns() syncs databaseDialect from Superset columns API
- saveJob() sends undefined for database_dialect="unknown" to force re-detect
- Backend: added direct_db+connection_id validation on update (mirroring create)
- Removed redundant "Язык ист." column from TranslationPreview table
- Removed unused getDetectedLang function
Tests:
- TranslationJobModel: datasourceId save mapping, dialect sync, unknown→undefined
- TranslateJobService: reject direct_db without connection_id, preserve existing
Verified: browser — translate_cross datasource persisted after save+reload,
dialect detected as "clickhouse", columns loaded (2), translation column preserved.