feat(instance): data locations as precise as a country or a state

halkyon_shared's 96f2d14: 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, and the app adds "(EU)" to a member
country and the country to a subdivision ("Germany (EU)", "California,
United States") under the most specific flag there is. deploy/.env and
the backups' guide say so; a Storage Box is named by its country now.
The package registers its notices (the flags, CLDR's subdivision
names); Learn's own CLDR notice for the world map stays, its
registration renamed to say so.

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

halkyon_learn_server/pubspec.yaml

@@ -20,7 +20,7 @@ dependencies:
     git:
       url: https://code.halkyon.app/project-halkyon/halkyon_shared.git
       path: packages/halkyon_base_server
-      ref: e23cc77f7c30a2a07015237ef0f054d1d1ccad2b
+      ref: 96f2d1461803599bdf5b14783f4b3d3a2810742f
   # Reads the pages profile links point to, for their rel="me" back-links.
   html: ^0.15.6
   # Mails email sign-in's codes over SMTP (ADR 0010).