Scaffold the Flutter app with Italian l10n and region configuration

Creates the app skeleton and the seam everything else in the project hangs
off: region-specific data lives in an asset file, not in code, so adding a
region later is a new JSON file rather than a refactor.

Notable choices:

- applicationId and namespace are it.nuvolari.app rather than the doubled
  it.nuvolari.nuvolari that `flutter create` produces, with the Kotlin package
  and the iOS bundle identifiers moved to match.
- SDK levels are pinned instead of inherited from `flutter.*`. Google Play
  requires API 36, and that is a release blocker rather than something to let a
  Flutter upgrade change silently. minSdk 24 is the highest floor the planned
  dependencies impose.
- Riverpod and Dio-free for now, no code generation: see docs/stack-decisions.md.
- Italian is the l10n source language, so app_it.arb is the template rather
  than a translation of an English original.

The region parser rejects rather than repairs. An inverted bounding box, a map
centre outside its own bounds, an unknown adapter name, a duplicate zone code
or an empty attribution list all throw with the offending field named. Each of
those would otherwise fail silently and visibly wrong: a swapped latitude and
longitude renders the radar in the wrong place, an unknown adapter falling back
to mock would show demo frames where live data was expected, and a missing
attribution is a licence violation rather than a cosmetic gap.

Tests run against the asset that actually ships and against a captured copy of
the live ARPA CAP feed, so the eleven zone codes in the config are checked
against the eleven the feed really emits rather than against a list retyped
from documentation.

Verified: dart format clean, flutter analyze 0 issues, 50 tests passing,
flutter build appbundle --debug produces an AAB with applicationId
it.nuvolari.app, minSdk 24, targetSdk 36.

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

Nuvolari/app/ios/Runner.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?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>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

Nuvolari/app/ios/Runner.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -0,0 +1,8 @@
+<?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>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>