Epic: Battery Saver Mode

_written by @carlos-zamora_

It'd be cool if Windows Terminal could be smart about battery consumption when in Low Power Mode or running on a battery (as opposed to a desktop being plugged in). Here's some ideas on what behavior could change:

- Acrylic ideas:
- Replace acrylic with mica
- Disable acrylic / fall back to HostBackdropAcrylic when in low power mode
- See also #7158 - disable that fix when in battery saver mode
- also #11092
- Renderer: reduce refresh rate
- [ ] #5318 Cursor: blink less often or don't blink at all

### Battery saving optimizations we should just do regardless
- [ ] #12706
- [ ] #1989

Put your ideas below!

Start by reviewing the related issues listed in this epic, including #7158, #11092, #5318, #12706, and #1989, and determine which battery-saving behavior is independently scoped. Done requires an agreed optimization with defined behavior for low-power or battery operation, rather than addressing the entire collection of ideas at once.

Written by the indexing model from the issue text.