chore(mobile): upgrade to Expo SDK 56

Bump expo, react, react-native, and all expo-* / react-native-* peers to
the SDK 56 line via expo install --fix, adding expo-splash-screen and
expo-system-ui for config plugins the SDK split out of core. Bump
@bacons/apple-targets, react-native-view-shot, and other native modules
to versions compatible with React Native 0.85 and the new architecture.

Remove @react-navigation/* direct dependencies and route their hooks
through expo-router, which is no longer compatible with react-navigation
as of SDK 56. Fix RN 0.85's removed StyleSheet.absoluteFillObject (use
absoluteFill) and react-native-view-shot 5.x's ViewShotRef type across
call sites. Downgrade eslint-plugin-react-hooks v7's new React Compiler
era rules to warnings pending a dedicated refactor, and repair Jest
fallout from the jest-expo/reanimated/worklets/expo-media-library bumps.

Regenerate the committed ios/ and android/ native projects with
`expo prebuild --clean` (required for @bacons/apple-targets 5.x) against
the production release channel, and document that requirement.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/mobile/targets/widget/generated.entitlements

@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-  <dict>
-    <key>com.apple.security.application-groups</key>
-    <array>
-      <string>group.com.sauci.app</string>
-    </array>
-  </dict>
-</plist>