feat(admin): implement pregnancy and birth management features

- Added new admin functionalities to force pregnancy, clear pregnancy, and trigger birth for characters.
- Introduced corresponding routes and controller methods in adminRouter and adminController.
- Enhanced the FalukantCharacter model to include pregnancy-related fields.
- Created database migration for adding pregnancy columns to the character table.
- Updated frontend views and internationalization files to support new pregnancy and birth management features.
- Improved user feedback and error handling for these new actions.

backend/sql/add_character_pregnancy.sql

@@ -0,0 +1,6 @@
+-- Optional: manuell ausführen, falls Migration nicht genutzt wird
+ALTER TABLE falukant_data."character"
+  ADD COLUMN IF NOT EXISTS pregnancy_due_at TIMESTAMPTZ NULL;
+ALTER TABLE falukant_data."character"
+  ADD COLUMN IF NOT EXISTS pregnancy_father_character_id INTEGER NULL
+    REFERENCES falukant_data."character"(id) ON DELETE SET NULL;