halkyon_app: data locations as precise as a country or a state

An operator's DATA_LOCATION and BACKUP_LOCATION may name a subdivision
(ISO 3166-2, US-CA, DE-BY) besides the EU or a country. The app adds
"(EU)" to a member country and the country to a subdivision ("Germany
(EU)", "California, United States", "Bavaria, Germany (EU)"), in
English and German, and shows the most specific flag there is: a
subdivision's own where the flag package has one, else its country's.
Subdivision names come from Unicode CLDR 48.2 (tool/subdivision_names.py),
bundled with their licence, which the app registers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_app/pubspec.yaml

@@ -60,3 +60,8 @@ flutter:
   assets:
     # flag-icons' MIT notice, for the licence list (registerFlagIconsLicense).
     - assets/flags/LICENSE-flag-icons.txt
+    # Unicode CLDR's names of subdivisions (states, regions) in English and
+    # German (AssetSubdivisionNames; tool/subdivision_names.py writes them),
+    # and its licence's notice (registerCldrLicense).
+    - assets/subdivisions/subdivisions.json
+    - assets/subdivisions/LICENSE-CLDR.txt