implemented adding sub tasks

frontend/src/routes/task/Add.svelte

@@ -8,10 +8,11 @@
     import MarkdownEditor from '../../Components/MarkdownEditor.svelte';
     import MemberEditor from '../../Components/MemberEditor.svelte';
 
-    let { project_id = null } = $props();
+    let { project_id = null, parent_task_id } = $props();
     let error = $state(null);
     let project = $state(null);
     let extendedSettings = $state(false);
+    let parent_task = $state(null);
     let task = $state({
         name : '',
         description : { source : '', rendered : '' },
@@ -24,7 +25,8 @@
     });
     let router = useTinyRouter();
 
-    function load(){
+    async function load(){
+        if (parent_task_id) await loadParent();
         if (project_id) loadProject();
     }
 
@@ -37,6 +39,21 @@
         console.log({drop:member.user.id});
     }
 
+    async function loadParent(){
+        const url = api(`task/${parent_task_id}`);
+        const resp = await fetch(url,{credentials:'include'});
+        if (resp.ok){
+            parent_task = await resp.json();
+            task.parent_task_id = +parent_task_id;
+            project_id = parent_task.project_id;
+            console.log({prj:project_id});
+            error = null;
+            project = null; // TODO
+        } else {
+            error = await resp.text();
+        }
+    }
+
     async function loadProject(){
         var url = api(`project/${project_id}`);
         const resp = await fetch(url,{credentials:'include'});
@@ -103,6 +120,17 @@
                 </td>
             </tr>
             {/if}
+            {#if parent_task}
+            <tr>
+                <th>
+                    {t('parent_task')}
+                </th>
+                <td>
+                    {parent_task.name}
+                </td>
+            </tr>
+            {/if}
+
             <tr>
                 <th>
                     {t('description')}