Replace the throwaway debug screen with the first real calendar UI and a
functional Month <-> Week switcher, on Material 3 Expressive.
Month view (S1):
- Material 3 Expressive card-per-day grid; only the current month's weeks
render (neighbouring days left blank)
- per-day event dots with "+N" overflow, today via primaryContainer
- spring-based press feedback from the active motion scheme
- swipe + drawer navigation, Loading/Failure/Success states
Week view (S2):
- vertical time schedule with overlap-resolved lanes (per-day clipping,
midnight spanning, instant events)
- all-day / multi-day events as connected horizontal spans
- single scroll container (gutter + day columns stay aligned), columns
bundled in a rounded container, noon-centred on load
- top section colour-shifts with the app bar on scroll; swipe navigation,
three states
Shared / infra:
- CalendarHost holds the active view; RootScreen renders it post-permission
- ui/common building blocks: CalendarDrawer, CalendarFailure,
ViewSwitcherPill, pastelize, observable locale, M3 Expressive slide
transition (motionScheme fastSpatialSpec)
- unit tests for the week layout (lanes, clipping, all-day spans)
- build: compileSdk 37, material3 pinned to 1.5.0-alpha21 for Expressive
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>