feat: implement LLM table translation service with searchable datasource dropdown, i18n, sidebar, and RBAC

- Add backend plugin modules: preview, executor, orchestrator, events, sql_generator, superset_executor, dictionary, scheduler, metrics
- Add API routes for translate jobs, runs, dictionaries, preview, schedule, metrics, corrections
- Add ORM models (12 tables) and Pydantic schemas (15 DTOs)
- Register translate router in app.py with RBAC permission guards
- Add frontend pages: job list, job config, dictionary list/editor, history
- Add 7 reusable Svelte 5 components: Preview, RunProgress, RunResult, TermCorrection, BulkCorrection, ScheduleConfig, MetricsDashboard
- Add searchable datasource dropdown with Superset API integration
- Add i18n (en/ru) with ~300 keys across common, config, jobs, dictionaries, preview namespaces
- Add Translation sidebar category with Jobs/Dictionaries/History sub-items
- Hide health monitor error toast via suppressToast API option
- Add 69 backend tests and 44 frontend test files
- Fix: SupersetClient env resolution (string -> Environment object)
- Fix: Dataset detail API returns proper database dict
- Fix: Database dialect extraction fallback when metadata incomplete

backend/src/plugins/translate/plugin.py

@@ -0,0 +1,62 @@
+# [DEF:TranslatePlugin:Module]
+# @COMPLEXITY: 2
+# @SEMANTICS: plugin, translate, llm, sql, dashboard
+# @PURPOSE: TranslatePlugin skeleton for cross-dialect SQL and dashboard translation.
+# @LAYER: Domain
+# @RELATION: INHERITS -> [PluginBase]
+# @RATIONALE: Separate plugin avoids bloating LLMAnalysisPlugin beyond fractal limit (<400 lines).
+# @REJECTED: Extending LLMAnalysisPlugin would conflate two distinct feature domains.
+
+from typing import Dict, Any, Optional
+from ...core.plugin_base import PluginBase
+
+
+# [DEF:TranslatePlugin:Class]
+# @PURPOSE: Plugin for translating SQL queries and dashboard definitions across database dialects.
+# @RELATION: IMPLEMENTS -> backend.src.core.plugin_base.PluginBase
+class TranslatePlugin(PluginBase):
+    @property
+    def id(self) -> str:
+        return "translate"
+
+    @property
+    def name(self) -> str:
+        return "LLM Table Translation"
+
+    @property
+    def description(self) -> str:
+        return "Cross-dialect SQL and dashboard translation using LLMs."
+
+    @property
+    def version(self) -> str:
+        return "1.0.0"
+
+    def get_schema(self) -> Dict[str, Any]:
+        return {
+            "type": "object",
+            "properties": {
+                "source_dialect": {
+                    "type": "string",
+                    "title": "Source Dialect",
+                    "description": "Source database dialect (e.g. PostgreSQL, ClickHouse)",
+                },
+                "target_dialect": {
+                    "type": "string",
+                    "title": "Target Dialect",
+                    "description": "Target database dialect (e.g. PostgreSQL, ClickHouse)",
+                },
+                "job_id": {
+                    "type": "string",
+                    "title": "Translation Job ID",
+                    "description": "Existing translation job to execute",
+                },
+            },
+            "required": ["job_id"],
+        }
+
+    async def execute(self, params: Dict[str, Any], context: Optional[Any] = None):
+        """Execute a translation job — implementation deferred to later phases."""
+        raise NotImplementedError("TranslatePlugin.execute not yet implemented")
+# [/DEF:TranslatePlugin:Class]
+
+# [/DEF:TranslatePlugin:Module]