Fix 500 error, add Address/Contact placeholders, and enhance Person activity view

- Fixed broken import path in /core dashboard
- Simplified core layout data requirements to prevent crashes
- Implemented V3 CRUD and Dexie tables for Addresses and Contacts
- Created placeholder management pages for /core/addresses and /core/contacts
- Added 'Linked Activity & Content' section to Person detail page to show related events and posts

src/routes/core/+page.ts

@@ -1,8 +1,16 @@
 import type { PageLoad } from './$types';
+import { error } from '@sveltejs/kit';
 
 export const load: PageLoad = async ({ parent }) => {
-    const parentData = await parent();
+    const data = await parent();
+    
+    if (!data.account_id) {
+        console.error('Core Dashboard: No account_id found in parent data');
+        // We could throw an error here, but for now let's just log it and return
+        // to avoid a hard crash if the user is just navigating.
+    }
+    
     return {
-        account_id: parentData.account_id
+        account_id: data.account_id
     };
-};
+};