feat: add products/cases pages and lead-capture form block

- types: Product/CaseStudy page types, CaseStudyBlockValue, FormBlockValue
- services: product.service.ts, case.service.ts
- app/products, app/cases: list + detail pages
- blocks: CaseStudyCard, LeadForm (submits to /api/v1/custom/leads/)
- Header nav: add 产品/案例 links

types/wagtail.ts

@@ -75,6 +75,34 @@ export interface LogoCloudBlockValue {
   logos: { url: string; title: string }[];
 }
 
+export interface CaseStudyBlockValue {
+  case_page: WagtailPageSummary | null;
+  summary?: string;
+}
+
+/** 与后端 apps/forms/models.py FIELD_TYPE_CHOICES 保持一致 */
+export type FormFieldType = "text" | "textarea" | "email" | "tel" | "select";
+
+export interface FormFieldDef {
+  label: string;
+  field_key: string;
+  field_type: FormFieldType;
+  required: boolean;
+  choices: string[];
+}
+
+export interface FormDefinitionValue {
+  id: number;
+  name: string;
+  submit_button_text: string;
+  success_message: string;
+  fields: FormFieldDef[];
+}
+
+export interface FormBlockValue {
+  form: FormDefinitionValue | null;
+}
+
 export type StreamFieldBlock =
   | { id: string; type: "hero"; value: HeroBlockValue }
   | { id: string; type: "stats"; value: StatsBlockValue }
@@ -82,6 +110,8 @@ export type StreamFieldBlock =
   | { id: string; type: "faq"; value: FAQBlockValue }
   | { id: string; type: "cta"; value: CTABlockValue }
   | { id: string; type: "logo_cloud"; value: LogoCloudBlockValue }
+  | { id: string; type: "case_study"; value: CaseStudyBlockValue }
+  | { id: string; type: "form"; value: FormBlockValue }
   | { id: string; type: "richtext"; value: string };
 
 export interface HomePageDetail extends WagtailPageSummary {
@@ -98,3 +128,22 @@ export interface BlogPageSummary extends WagtailPageSummary {
 export interface BlogPageDetail extends BlogPageSummary {
   body: StreamFieldBlock[];
 }
+
+export interface ProductPageSummary extends WagtailPageSummary {
+  summary?: string;
+}
+
+export interface ProductPageDetail extends ProductPageSummary {
+  body: StreamFieldBlock[];
+}
+
+export interface CaseStudyPageSummary extends WagtailPageSummary {
+  client_name: string;
+  industry?: string;
+  published_at?: string;
+  summary?: string;
+}
+
+export interface CaseStudyPageDetail extends CaseStudyPageSummary {
+  body: StreamFieldBlock[];
+}