feat: add products/cases page models and forms lead-capture app

- apps/products: ProductIndexPage/ProductPage
- apps/cases: CaseStudyIndexPage/CaseStudyPage
- apps/forms: FormDefinition/FormDefinitionField/Lead + submit API
- core/blocks: CaseStudyBlock, FormBlock (with API representation)
- register new apps, custom leads API route, migrations

apps/core/blocks.py

@@ -5,6 +5,7 @@
 from django.utils.translation import gettext_lazy as _
 from wagtail import blocks
 from wagtail.images.blocks import ImageChooserBlock
+from wagtail.snippets.blocks import SnippetChooserBlock
 
 
 class CTAButtonBlock(blocks.StructBlock):
@@ -97,6 +98,59 @@ class LogoCloudBlock(blocks.StructBlock):
         template = "core/blocks/logo_cloud_block.html"
 
 
+class CaseStudyBlock(blocks.StructBlock):
+    case_page = blocks.PageChooserBlock(
+        page_type="cases.CaseStudyPage", label=_("案例页面")
+    )
+    summary = blocks.CharBlock(max_length=250, required=False, label=_("摘要覆盖"))
+
+    class Meta:
+        icon = "doc-full"
+        label = _("客户案例卡片")
+
+
+class FormBlock(blocks.StructBlock):
+    """嵌入可复用的线索表单（apps.forms.FormDefinition Snippet）。"""
+
+    form = SnippetChooserBlock("forms.FormDefinition", label=_("选择表单"))
+
+    class Meta:
+        icon = "form"
+        label = _("线索表单")
+
+    def get_api_representation(self, value, context=None):
+        """
+        默认 SnippetChooserBlock 只会序列化为主键，前端渲染动态表单需要完整字段定义，
+        因此这里手动展开 FormDefinition 及其子字段（详见 apps/forms/models.py）。
+        """
+        form_def = value.get("form")
+        if form_def is None:
+            return {"form": None}
+        return {
+            "form": {
+                "id": form_def.pk,
+                "name": form_def.name,
+                "submit_button_text": form_def.submit_button_text,
+                "success_message": form_def.success_message,
+                "fields": [
+                    {
+                        "label": field.label,
+                        "field_key": field.field_key,
+                        "field_type": field.field_type,
+                        "required": field.required,
+                        "choices": [
+                            choice.strip()
+                            for choice in field.choices.split(",")
+                            if choice.strip()
+                        ],
+                    }
+                    for field in form_def.fields.all()
+                ],
+            }
+        }
+
+
+
 COMMON_BLOCKS = [
     ("hero", HeroBlock()),
     ("stats", StatsBlock()),
@@ -104,5 +158,7 @@ COMMON_BLOCKS = [
     ("faq", FAQBlock()),
     ("cta", CTABlock()),
     ("logo_cloud", LogoCloudBlock()),
+    ("case_study", CaseStudyBlock()),
+    ("form", FormBlock()),
     ("richtext", blocks.RichTextBlock(label=_("富文本"))),
 ]