fix(llm): add fetch-models endpoint, fix SQL Lab INSERT (client_id truncation, sync mode, target_column, timestamp normalization)

- Add POST /api/llm/providers/fetch-models route with LLMClient.fetch_models()
- Add target_column to TranslationJob model/schema/service/orchestrator
- Fix SQL Lab execute: truncate client_id to 11 chars (varchar(11))
- Switch SQL Lab to sync mode (runAsync: false) — no Celery workers
- Fix polling: unwrap nested result from Superset query API
- Fix ClickHouse timestamp: normalize float timestamps to YYYY-MM-DD

backend/tests/scripts/test_clean_release_cli.py

@@ -1,6 +1,5 @@
 # [DEF:test_clean_release_cli:Module]
 # @RELATION: BELONGS_TO -> SrcRoot
-# @COMPLEXITY: 3
 # @PURPOSE: Smoke tests for the redesigned clean release CLI.
 # @LAYER: Domain
 

backend/tests/scripts/test_clean_release_tui.py

@@ -1,6 +1,5 @@
 # [DEF:TestCleanReleaseTui:Module]
 # @RELATION: BELONGS_TO -> SrcRoot
-# @COMPLEXITY: 3
 # @SEMANTICS: tests, tui, clean-release, curses
 # @PURPOSE: Unit tests for the interactive curses TUI of the clean release process.
 # @LAYER: Scripts

backend/tests/scripts/test_clean_release_tui_v2.py

@@ -1,6 +1,5 @@
 # [DEF:test_clean_release_tui_v2:Module]
 # @RELATION: BELONGS_TO -> SrcRoot
-# @COMPLEXITY: 3
 # @PURPOSE: Smoke tests for thin-client TUI action dispatch and blocked transition behavior.
 # @LAYER: Domain