Add project soft-delete with workspace archival

- Add delete button (×) to sidebar project list, shown on hover
- Soft-delete: mark projects as deleted in DB instead of hard delete
- Move workspace files to /app/data/deleted/ folder on deletion
- Filter deleted projects from list query
- Auto-select next project after deleting current one
- Also includes agent prompt improvements for reverse proxy paths

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/components/Sidebar.vue

@@ -9,7 +9,15 @@ defineProps<{
 const emit = defineEmits<{
   select: [id: string]
   create: []
+  delete: [id: string]
 }>()
+
+function onDelete(e: Event, id: string) {
+  e.stopPropagation()
+  if (confirm('确定删除这个项目？')) {
+    emit('delete', id)
+  }
+}
 </script>
 
 <template>
@@ -26,7 +34,10 @@ const emit = defineEmits<{
         :class="{ active: project.id === selectedId }"
         @click="emit('select', project.id)"
       >
-        <span class="project-name">{{ project.name }}</span>
+        <div class="project-row">
+          <span class="project-name">{{ project.name }}</span>
+          <button class="btn-delete" @click="onDelete($event, project.id)" title="删除项目">×</button>
+        </div>
         <span class="project-time">{{ new Date(project.updated_at).toLocaleDateString() }}</span>
       </div>
     </nav>
@@ -96,9 +107,46 @@ const emit = defineEmits<{
   border-left: 3px solid var(--accent);
 }
 
+.project-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+}
+
 .project-name {
   font-size: 14px;
   font-weight: 500;
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.btn-delete {
+  display: none;
+  width: 20px;
+  height: 20px;
+  padding: 0;
+  border: none;
+  background: transparent;
+  color: var(--text-secondary);
+  font-size: 16px;
+  line-height: 1;
+  cursor: pointer;
+  border-radius: 4px;
+  flex-shrink: 0;
+}
+
+.btn-delete:hover {
+  background: var(--error, #e74c3c);
+  color: #fff;
+}
+
+.project-item:hover .btn-delete {
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 .project-time {