fix(map): a region is picked on a screen of its own, and a country's map offered once it is picked

The composer showed the map inside its scrolling page, so zooming and
scrolling fought over the wheel. A map question's answer is now a field
that opens the map in the whole window, as a studyset's description is
written, with Save in the app bar; nothing scrolls there, so the wheel
alone zooms. The Prefectures chip stood beside East Asia's countries
before Japan was picked; it now shows once Japan, or a prefecture, is.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/l10n/app_localizations_en.dart

@@ -3393,6 +3393,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get mapNonePicked => 'No region picked yet';
 
+  @override
+  String get mapPickTitle => 'Pick the region';
+
   @override
   String get mapNameJapan => 'Japan';
 
@@ -3471,6 +3474,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get composerLabelRegion => 'Answer';
 
+  @override
+  String get composerRegionPick => 'Tap to pick the region on the map';
+
   @override
   String get homeStreakTooltip => 'Study streak';