fix: persist environment selection, support Kilo AI provider, resolve Superset virtual columns for translation preview

- Add environment_id to TranslationJob model/schema/API + DB migration
- Pass environmentId from page to TranslationPreview and fetchPreview
- Fix _fetch_sample_rows: use result_type='samples' to include virtual cols
- Add 'kilo' and 'openrouter' to supported LLM provider types
- Make response_format conditional (skip for non-OpenAI upstream providers)
- Remove source_table field from form (redundant with datasource)
- Restore datasourceSearch display from saved job on page load
- Add request/response logging for LLM API calls

.opencode/opencode.jsonc

@@ -5,7 +5,7 @@
 	"type": "local",
       "command": ["npx", "chrome-devtools-mcp@latest",
         "--browser-url=http://127.0.0.1:9222" ],
-        "enabled": false
+        "enabled": true
     },
         "axiom": {
       "type": "local",