chore(deps): migrate to Expo SDK 56 (Phase 1 - compat)

Compatibility migration from SDK 55 to SDK 56 (react-native-tvos 0.85.3-0,
React 19.2.3). Phase 1 = breaking changes needed to build; new-feature
adoption and TypeScript 6 are deferred to Phase 2.

- Deps aligned to SDK 56 via `expo install --fix` (all expo-* 56.x, screens
  4.25.2, reanimated 4.3.1, worklets 0.8.3, gesture-handler 2.31.x, svg 15.15.4)
- react-native -> react-native-tvos@0.85.3-0; react/react-dom 19.2.3
- expo-router forked React Navigation: ran the SDK 56 codemod
  (@react-navigation/* imports -> expo-router/*), removed the 3 now-unused
  direct @react-navigation/* dependencies, retyped NestedTabPageStack via
  expo-router Stack.Screen options
- StyleSheet.absoluteFillObject -> absoluteFill (removed from RN 0.85 types)
- app.json ios.deploymentTarget 15.6 -> 16.4 (SDK 56 minimum)
- CI: Xcode 26.2 -> 26.4; made xcode-version Renovate-managed via a
  customManager + xcodereleases customDatasource
- @babel/core 7.29.7; dropped version-locked screens/codegen bun-patches
  (no longer applicable on SDK 56)

Deferred to Phase 2: TypeScript 6 (toolchain: @types/node, jest globals,
UdpSocket typing), @expo/vector-icons -> @react-native-vector-icons codemod.

typecheck passes. expo-doctor: 2 known failures remain (react-native-track-player
New Arch fork; typescript major mismatch pending the deferred TS6 bump).

.github/renovate.json

@@ -25,6 +25,25 @@
   "osvVulnerabilityAlerts": true,
   "configMigration": true,
   "separateMinorPatch": true,
+  "customManagers": [
+    {
+      "customType": "regex",
+      "managerFilePatterns": ["/\\.ya?ml$/"],
+      "matchStrings": [
+        "# renovate: datasource=(?<datasource>\\S+) depName=(?<depName>\\S+)(?: versioning=(?<versioning>\\S+))?\\s+xcode-version:\\s*[\"']?(?<currentValue>[^\"'\\s]+)"
+      ],
+      "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}loose{{/if}}"
+    }
+  ],
+  "customDatasources": {
+    "xcode": {
+      "defaultRegistryUrlTemplate": "https://xcodereleases.com/data.json",
+      "format": "json",
+      "transformTemplates": [
+        "{ \"releases\": [$[version.release.release=true].{\"version\": version.number}] }"
+      ]
+    }
+  },
   "lockFileMaintenance": {
     "vulnerabilityAlerts": {
       "enabled": true,