Refactor saveMember function to improve duplicate member handling and streamline member updates. Enhance error messaging for non-existent members and ensure new members are added with default active status.

server/utils/members.js

@@ -242,10 +242,10 @@ export async function saveMember(memberData) {
   const members = await readMembers()
   
   if (memberData.id) {
-    // Update existing
+    // Update existing manual member if present.
+    // If the ID belongs to a login-only member shown in the merged list,
+    // create a manual overlay with the same ID so editable fields can be stored.
     const index = members.findIndex(m => m.id === memberData.id)
-    if (index !== -1) {
-      // Check for duplicate (excluding current member)
     const duplicate = findDuplicateMember(
       members.filter(m => m.id !== memberData.id),
       memberData.firstName,
@@ -257,9 +257,13 @@ export async function saveMember(memberData) {
       throw new Error('Ein Mitglied mit diesem Namen und Geburtsdatum existiert bereits.')
     }
 
+    if (index !== -1) {
       members[index] = { ...members[index], ...memberData }
     } else {
-      throw new Error('Mitglied nicht gefunden')
+      members.push({
+        ...memberData,
+        active: typeof memberData.active === 'boolean' ? memberData.active : true
+      })
     }
   } else {
     // Add new - check for duplicate first