支持段落删除与移动排序，修复导出残留与外键约束

- 前端：段落列表/配置区/手动编辑区新增上移、下移、删除按钮，hover 显示
- 前端：移动和删除操作后自动保存到后端，修正 canDeleteBlock 判定逻辑
- 后端：保存段落时级联删除关联的 generation_logs 再删段落
- 后端：导出时清理未被引用的标题段落及其内容，避免已删段落残留在 Word 中
- 后端：删除模板时级联清理 generation_logs/documents/paragraphs

backend/services/document_export.py

@@ -32,6 +32,43 @@ def _delete_block(block):
         parent.remove(element)
 
 
+def _delete_heading_section(heading: Paragraph):
+    blocks = [heading]
+    current = heading._element.getnext()
+    while current is not None:
+        if isinstance(current, CT_P):
+            para = Paragraph(current, heading._parent)
+            if _is_heading(para):
+                break
+            blocks.append(para)
+        elif isinstance(current, CT_Tbl):
+            blocks.append(Table(current, heading._parent))
+        current = current.getnext()
+    for block in blocks:
+        _delete_block(block)
+
+
+def _remove_unreferenced_headings(document: DocumentObject, referenced_anchors: set[str]):
+    headings_to_remove: list[Paragraph] = []
+    found_first_heading = False
+    pre_heading_blocks: list = []
+    print(f"[EXPORT] referenced_anchors: {referenced_anchors}")
+    for block in _iter_block_items(document):
+        if isinstance(block, Paragraph) and _is_heading(block):
+            found_first_heading = True
+            text = block.text.strip()
+            if text not in referenced_anchors:
+                print(f"[EXPORT] Unreferenced heading found, will remove: '{text}'")
+                headings_to_remove.append(block)
+        elif not found_first_heading:
+            pre_heading_blocks.append(block)
+    for heading in headings_to_remove:
+        _delete_heading_section(heading)
+    if not referenced_anchors:
+        for block in pre_heading_blocks:
+            _delete_block(block)
+
+
 def _clear_paragraph(paragraph: Paragraph):
     element = paragraph._element
     for child in list(element):
@@ -332,10 +369,22 @@ def _replace_section_group(
 
 def export_document_bytes(template_bytes: bytes, logs: list[dict]) -> bytes:
     document = Document(BytesIO(template_bytes))
+
+    referenced_anchors: set[str] = set()
+    for item in logs:
+        for key in ("anchor_title", "title"):
+            val = (item.get(key) or "").strip()
+            if val:
+                referenced_anchors.add(val)
+
+    print(f"[EXPORT] logs count={len(logs)}, anchor_titles={[(l.get('anchor_title'), l.get('title')) for l in logs]}")
+
     last_heading_element = None
     for group in _group_logs(logs):
         last_heading_element = _replace_section_group(document, group, last_heading_element)
 
+    _remove_unreferenced_headings(document, referenced_anchors)
+
     output = BytesIO()
     document.save(output)
     return output.getvalue()