Restructure Core management into linkable routes and add common layout navigation

- Renamed person route to people for consistency
- Refactored /core dashboard to use standard <a> links
- Added common management <nav> to core layout
- Replaced goto() with standard links across all list and detail pages
- Fixed 500 error caused by broken import path and strict layout data

src/routes/core/users/+page.svelte

@@ -103,9 +103,9 @@
                             <span>{user.email || '--'}</span>
                         </div>
                     </div>
-                    <button class="btn btn-sm variant-filled-primary w-full" onclick={() => goto(`/core/users/${user.user_id_random}`)}>
+                    <a class="btn btn-sm variant-filled-primary w-full" href="/core/users/{user.user_id_random}">
                         Edit User
-                    </button>
+                    </a>
                 </div>
             {/each}
         </div>