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/docs/roadmap.md

@@ -7,7 +7,7 @@ Legend: ✅ done · 🔨 in progress · ⛔ blocked on credentials from the proj
 
 ---
 
-## M0 — Toolchain and repository hygiene 🔨
+## M0 — Toolchain and repository hygiene ✅
 
 Flutter 3.47.3 stable, Android SDK (platform-tools, platform 36, build-tools 36.0.0),
 JDK 21, environment variables. Commit the removal of the old Xamarin skeleton.
@@ -15,7 +15,13 @@ JDK 21, environment variables. Commit the removal of the old Xamarin skeleton.
 **Accepts when:** `flutter doctor -v` reports no blocking Android toolchain error and
 `git status` is clean.
 
-## M1 — Scaffold, Italian l10n, region config, CI
+**Done.** `flutter doctor -v` reports "No issues found!". Installed: Flutter 3.47.3 at
+`C:\src\flutter` (telemetry disabled), Android SDK at `C:\Android\Sdk` with
+platform 36, build-tools 36.0.0, platform-tools and all licences accepted, and
+`JAVA_HOME` pointing at the JDK 21 a previous Visual Studio install had already left
+on the machine.
+
+## M1 — Scaffold, Italian l10n, region config, CI 🔨
 
 `flutter create` with applicationId `it.nuvolari.app`; `flutter_localizations` + `intl`
 with `app_it.arb` as template and no hardcoded UI strings; `RegionConfig` loaded from