Add ANR Rate / App Hang Rate to Release Details page

### Problem Statement

The Release Details page currently supports metrics like Crash Free Session Rate, Crash Free User Rate, Session Count, and others in its graph and comparison table. However, ANR Rate (anr_rate()) and App Hang Rate are not available as selectable metrics on this page, even though they are available in dashboards and on the project overview page.

Teams that monitor ANR/App Hang rate as a key quality signal are forced to maintain a separate custom dashboard to track this metric per release, instead of being able to view it alongside crash free rates and session counts in the Release Details view.

### Solution Brainstorm

- Add anr_rate() / foreground_anr_rate() (Android) and App Hang Rate (iOS) as selectable metrics in the Release Details graph.
- Optionally include them in the comparison table below the graph, alongside crash free session/user rate.

### Product Area

Releases

Start with the Release Details page and compare how ANR Rate, foreground ANR Rate, and App Hang Rate are exposed in dashboards and the project overview page. Trace the existing selectable metrics and comparison table, then confirm the relevant Android and iOS metrics can be selected for release views and determine whether they should also appear in the comparison table.

Written by the indexing model from the issue text.