refactor(ui,report): split Ultra config and batch-compare templates

- What: Move the Ultra backend configuration UI flow out of `src/ui/modern.py` into `src/ui/ultra_config.py`.
- What: Extract batch-compare HTML/CSS/JS templates from `src/features/batch_compare/report.py` into `src/features/batch_compare/templates/`.
- What: Reduce `modern.py` and `report.py` sizes to stay under the 500-line limit and improve separation of concerns.
- Why: Make complex UI/report rendering code easier to maintain and navigate.

Tests: not run (not provided)

Author: trend-denny-lee