[Refactor] Migrate settings feature to Jetpack Compose

(Sub-issue for #368)

## Tasks

* [ ] Add composables for preference list items
* [x] Base composable
* [x] Category group
* [x] Two-state item (switch, checkbox)
* [ ] Generic dialog preference
* [ ] Input dialog (will need to revisit the API design)
* [ ] List dialog (will need to revisit the API design)
* [ ] Migrate settings list screen to Compose
* [x] Migrate to list-detail pattern (partially blocked until Material3 Adaptive gets Jetpack Navigation support, see [b/294612000](https://issuetracker.google.com/issues/294612000)
* [ ] Migrate sub-pages
* [x] Migrate general page (now appearance settings)
* [ ] Move analytics settings to separate page
* [x] Migrate tasks page
* Migrate account page (tracked as part of account feature migration) - #585
* [ ] #922
* [ ] Expose settings navigation graph (#456)

*(Last updated 3 Aug 2025)*