Implement RFC 0002 (rfcs/0002-core-parity-and-correctness.md) across
Python, Swift, Kotlin, and the browser preview.

Runtime correctness
- Route use_effect and use_layout_effect errors to the nearest
  ErrorBoundary; post-commit Python errors no longer retire the surface.
- Keep Suspense siblings mounted (hidden) when a new descendant
  suspends.
- Step async components eagerly so resolved awaits render inline.
- Batch state updates automatically on every host; one render-storm
  policy (50 passes, RuntimeError through the boundary and RedBox).
- Dev warnings for unkeyed lists, setters after unmount or during
  render, in-place mutations, and changing dependency lengths.

Components, style, and accessibility
- Pressable disabled/delay_long_press/android_ripple and PressState;
  ScrollView horizontal, content_container_style, insets, throttle, drag
  and momentum events, snapping, keyboard persistence; Text
  ellipsize_mode, selectable, allow_font_scaling, pressable spans;
  TextInput selection, key presses, content size, keyboard appearance;
  Image load lifecycle, fade, headers; Modal on_request_close; StatusBar
  translucent/animated; FlatList/SectionList inverted, separators,
  initial index, sticky section headers.
- Typed event records (LayoutEvent, ScrollEvent, SelectionEvent,
  KeyPressEvent, ContentSizeEvent) and typed imperative handles
  (ViewHandle, TextInputHandle, ScrollViewHandle, WebViewHandle).
- border_style, inset shorthands, 3D transforms, DynamicColor on every
  renderer; pn.style typed with Unpack[Style].
- accessibility_value/actions/important_for_accessibility on every view.

Device APIs
- AccessibilityInfo, Keyboard, Dimensions, PixelRatio, Device,
  Localization modules with hooks; iOS keyboard height; Android camera
  full-resolution capture, location permission prompt; SecureStore
  raises on failure.

Navigation
- Navigator screen_options, Group, create_navigation_ref, pop_to,
  before_remove on every removal with an iOS guarded-back path,
  NavigationTheme with dark mode, tab bar styling, tab_bar_visible,
  freeze_on_blur, presentation and animation variants on iOS and
  Android, Android slide transitions, back arrow, inset-aware toolbar,
  large titles, and predictive back. The browser preview's native stacks
  draw navigation bars.

Animation and gestures
- React Native's decay model everywhere, composed iOS transform
  channels, Easing namespace with bezier passthrough, AnimationResult, a
  clear error for non-animatable props; gesture enabled flags, Pan
  offsets, max_pointers, min_velocity, and absolute coordinates.

Found on the simulator and emulator
- Events a view emits while its own commit applies carry that commit's
  identity, so a new Image's on_load_start arrives.
- Pressable spans are bounded by their glyphs; Android Text labels with
  on_press are clickable.
- Horizontal ScrollView content lays out in a row on every renderer.
- WebViewHandle.eval_js settles with the page's answer through an async
  WebViews module.
- iOS Pan gestures with activation offsets begin; iOS single-line fields
  report Enter; TextInputHandle.clear() reports on_change everywhere.
- A reopened Modal shows its content on iOS and Android; one iOS sheet
  pull-down is one on_request_close; on_dismiss fires on every renderer
  when visible turns false; overlay backdrop taps request close.

Testing, tooling, and docs
- Role, placeholder, and display-value queries, find_by_*, within,
  wait_for, a fake clock, and a pytest plugin.
- pn start names missing requirements with an exact install command.
- Regenerated native contracts, 115 e2e demos and Maestro flows, updated
  guides and API reference.

Removals
- The Python view-handler layer (NativeViewRegistry, ViewHandler,
  register_component, native_component, get_registry), scroll_axis,
  positional Context.Provider values, dict event payloads, Ref._pn_tag
  and _pn_frame, free-form easing strings, the eval_js view command, the
  unused requests dependency, duplicate equality helpers, and dead host
  hooks.

BREAKING CHANGE: Context.Provider takes value as a keyword; ScrollView
uses horizontal instead of scroll_axis; on_layout, on_scroll, and
on_selection_change deliver dataclasses; Pressable style callables
receive PressState; refs on built-in elements hold typed handles; sdk
register_component and native_component are replaced by
define_component; pythonnative.native_views.get_registry is replaced by
get_backend; Animated.decay uses React Native's model;
SecureStore.set_item and delete_item raise on failure; a Modal no longer
closes itself on a back press or backdrop tap and calls on_request_close
instead.