Add Zod validation to all API endpoints and remove debug test route

Adds schema-based input validation across helcim, events, members,
series, admin, and updates API endpoints. Removes the peer-support
debug test endpoint. Adds validation test coverage.

server/api/members/create.post.js

@@ -100,14 +100,24 @@ export default defineEventHandler(async (event) => {
 
     // TODO: Send welcome email
     
-    return { success: true, member }
+    return {
+      success: true,
+      member: {
+        id: member._id,
+        email: member.email,
+        name: member.name,
+        circle: member.circle,
+        contributionTier: member.contributionTier,
+        status: member.status
+      }
+    }
   } catch (error) {
     if (error.statusCode) {
       throw error
     }
-    throw createError({ 
-      statusCode: 400, 
-      statusMessage: error.message 
+    throw createError({
+      statusCode: 400,
+      statusMessage: 'Member creation failed'
     })
   }
 })