AI Assistant: Integration leftovers

[dmirgaev]

No description provided.

[Copilot]

Pull request overview

This PR cleans up leftovers from the AI Assistant integration: it consolidates the getGridExtraContext/getGridColumnExtraContext extension hooks into direct buildContext/buildColumnContext overrides, caches controller references, removes stale TODOs, and adds extensive test coverage including a new DataGrid integration test file.

Changes:

• Refactor AIAssistantIntegrationController to cache dataController/columnsController and replace the "extra context" hooks with overridable buildContext/buildColumnContext methods.
• Remove stale // TODO comments and unneeded as unknown as test casts.
• Significantly expand Jest coverage for AI assistant controllers (failure paths, headerText formatting, dispose behavior, second-request rejection) and add new DataGrid integration controller test file.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/devextreme/js/__internal/grids/grid_core/ai_assistant/commands/index.ts	Removed obsolete TODO comment.
packages/devextreme/js/__internal/grids/grid_core/ai_assistant/ai_assistant_integration_controller.ts	Cached controller refs; replaced extra-context hooks with overridable buildContext/buildColumnContext.
packages/devextreme/js/__internal/grids/grid_core/ai_assistant/tests/ai_assistant_integration_controller.integration.test.ts	Dropped unnecessary as unknown cast in test setup.
packages/devextreme/js/__internal/grids/grid_core/ai_assistant/tests/ai_assistant_controller.test.ts	Added tests for failure paths, header formatting, dispose, and request rejection.
packages/devextreme/js/__internal/grids/data_grid/ai_assistant/commands/index.ts	Removed obsolete TODO comment.
packages/devextreme/js/__internal/grids/data_grid/ai_assistant/ai_assistant_integration_controller.ts	Switched DataGrid overrides to new buildContext/buildColumnContext API.
packages/devextreme/js/__internal/grids/data_grid/ai_assistant/tests/ai_assistant_integration_controller.integration.test.ts	New integration test file for DataGrid AI assistant controller.
packages/devextreme/js/__internal/grids/data_grid/ai_assistant/tests/ai_assistant_controller.test.ts	New unit tests for DataGridAIAssistantController.