Problem

In the Android app's schedule screen, scrolling through the agenda, opening a session, and pressing back reset the scroll position to the top. The selected day was kept, but the scroll within the day was lost — forcing the user to scroll back down every time.

Root cause

Navigation Compose only composes the top destination. When you open a session detail, the ScheduleList destination leaves composition (its NavBackStackEntry stays on the back stack, but the composable tree is torn down). On popBackStack() it's composed fresh.

The per-day scroll states in ScheduleGridPager were held in a plain remember:

val gridStates = remember(agendas.size) { List(agendas.size) { LazyGridState() } }

Plain remember is discarded on tear-down, so the states came back as brand-new LazyGridState() instances at offset 0. The pager state survived because rememberPagerState is saveable — which is exactly why the day was preserved but the scroll wasn't.

Fix

Hold the grid states in rememberSaveable with a listSaver that persists each day's firstVisibleItemIndex + firstVisibleItemScrollOffset, plugging into the same SaveableStateHolder mechanism the back-stack entry uses. Saving the whole list under a single key avoids the per-iteration key-collision trap you'd hit building a list of rememberLazyGridState() calls in a loop.

The restore clamps the list to the current day count, so a changed agenda day-count can't cause an IndexOutOfBounds on gridStates[page].

Also adds the compose.runtimeSaveable dependency — the module previously only used the foundation wrappers, so androidx.compose.runtime.saveable wasn't on its compile classpath.

Testing

• ktlintCheck + detekt ✅
• :androidApp:lintDebug ✅
• Compiles for common / desktop / wasmJs / android ✅
• ⚠️ Not yet manually verified on a device — the change is a textbook remember → rememberSaveable fix, but a quick manual pass (scroll → open session → back) would confirm.

🤖 Generated with Claude Code