Add heir selection functionality in Falukant module

- Implemented getPotentialHeirs and selectHeir methods in FalukantService to allow users to retrieve and select potential heirs based on specific criteria.
- Updated FalukantController to wrap new methods with user authentication and added corresponding routes in FalukantRouter.
- Enhanced OverviewView component to display heir selection UI when no character is present, including loading states and error handling.
- Added translations for heir selection messages in both German and English locales to improve user experience.

backend/services/falukantService.js

@@ -2925,6 +2925,107 @@ class FalukantService extends BaseService {
         return { success: true, childCharacterId };
     }
 
+    async getPotentialHeirs(hashedUserId) {
+        const user = await getFalukantUserOrFail(hashedUserId);
+        
+        // Prüfe, ob der User bereits einen Charakter hat
+        const existingCharacter = await FalukantCharacter.findOne({ where: { userId: user.id } });
+        if (existingCharacter) {
+            throw new Error('User already has a character');
+        }
+
+        if (!user.mainBranchRegionId) {
+            throw new Error('User has no main branch region');
+        }
+
+        // Hole den noncivil Titel
+        const noncivilTitle = await TitleOfNobility.findOne({ where: { labelTr: 'noncivil' } });
+        if (!noncivilTitle) {
+            throw new Error('Noncivil title not found');
+        }
+
+        // Berechne das Datum für 10-14 Jahre alt (in Tagen)
+        const now = new Date();
+        now.setHours(0, 0, 0, 0);
+        const minDate = new Date(now);
+        minDate.setDate(minDate.getDate() - 14); // 14 Tage = 14 Jahre
+        const maxDate = new Date(now);
+        maxDate.setDate(maxDate.getDate() - 10); // 10 Tage = 10 Jahre
+
+        // Hole zufällige Charaktere aus der Hauptregion, die 10-14 Jahre alt sind
+        // und keinen userId haben (also noch keinem User zugeordnet sind)
+        // und den noncivil Titel haben
+        const potentialHeirs = await FalukantCharacter.findAll({
+            where: {
+                regionId: user.mainBranchRegionId,
+                userId: null,
+                titleOfNobility: noncivilTitle.id,
+                birthdate: {
+                    [Op.between]: [minDate, maxDate]
+                }
+            },
+            include: [
+                { model: FalukantPredefineFirstname, as: 'definedFirstName', attributes: ['name'] },
+                { model: FalukantPredefineLastname, as: 'definedLastName', attributes: ['name'] }
+            ],
+            order: Sequelize.fn('RANDOM'),
+            limit: 5
+        });
+
+        // Berechne das Alter für jeden Charakter
+        return potentialHeirs.map(heir => {
+            const age = calcAge(heir.birthdate);
+            return {
+                id: heir.id,
+                definedFirstName: heir.definedFirstName,
+                definedLastName: heir.definedLastName,
+                gender: heir.gender,
+                age: age
+            };
+        });
+    }
+
+    async selectHeir(hashedUserId, heirId) {
+        const user = await getFalukantUserOrFail(hashedUserId);
+        
+        // Prüfe, ob der User bereits einen Charakter hat
+        const existingCharacter = await FalukantCharacter.findOne({ where: { userId: user.id } });
+        if (existingCharacter) {
+            throw new Error('User already has a character');
+        }
+
+        // Hole den Erben-Charakter
+        const heir = await FalukantCharacter.findOne({
+            where: {
+                id: heirId,
+                userId: null // Stelle sicher, dass er noch keinem User zugeordnet ist
+            }
+        });
+
+        if (!heir) {
+            throw new Error('Heir not found or already assigned');
+        }
+
+        // Prüfe, ob der Erbe in der Hauptregion ist
+        if (heir.regionId !== user.mainBranchRegionId) {
+            throw new Error('Heir is not in main branch region');
+        }
+
+        // Prüfe das Alter (10-14 Jahre)
+        const age = calcAge(heir.birthdate);
+        if (age < 10 || age > 14) {
+            throw new Error('Heir age is not between 10 and 14');
+        }
+
+        // Weise den Charakter dem User zu
+        await heir.update({ userId: user.id });
+
+        // Benachrichtige den User
+        notifyUser(hashedUserId, 'falukantUserUpdated', {});
+
+        return { success: true, characterId: heir.id };
+    }
+
     async getPossiblePartners(requestingCharacterId) {
         const proposals = await MarriageProposal.findAll({
             where: {