feat: Added TypeScript version types, fetchTechniqueVersions function,…

- "frontend/src/api/public-client.ts"
- "frontend/src/pages/TechniquePage.tsx"

GSD-Task: S04/T03

frontend/src/api/public-client.ts

@@ -68,6 +68,18 @@ export interface TechniquePageDetail {
   key_moments: KeyMomentSummary[];
   creator_info: CreatorInfo | null;
   related_links: RelatedLinkItem[];
+  version_count: number;
+}
+
+export interface TechniquePageVersionSummary {
+  version_number: number;
+  created_at: string;
+  pipeline_metadata: Record<string, unknown> | null;
+}
+
+export interface TechniquePageVersionListResponse {
+  items: TechniquePageVersionSummary[];
+  total: number;
 }
 
 export interface TechniqueListItem {
@@ -217,6 +229,14 @@ export async function fetchTechnique(
   return request<TechniquePageDetail>(`${BASE}/techniques/${slug}`);
 }
 
+export async function fetchTechniqueVersions(
+  slug: string,
+): Promise<TechniquePageVersionListResponse> {
+  return request<TechniquePageVersionListResponse>(
+    `${BASE}/techniques/${slug}/versions`,
+  );
+}
+
 // ── Topics ───────────────────────────────────────────────────────────────────
 
 export async function fetchTopics(): Promise<TopicCategory[]> {

frontend/src/pages/TechniquePage.tsx

@@ -151,7 +151,17 @@ export default function TechniquePage() {
               "en-US",
               { year: "numeric", month: "short", day: "numeric" },
             );
-            return `Compiled from ${sourceCount} source${sourceCount !== 1 ? "s" : ""} · ${momentCount} key moment${momentCount !== 1 ? "s" : ""} · Last updated ${updated}`;
+            const parts = [
+              `Compiled from ${sourceCount} source${sourceCount !== 1 ? "s" : ""}`,
+              `${momentCount} key moment${momentCount !== 1 ? "s" : ""}`,
+            ];
+            if (technique.version_count > 0) {
+              parts.push(
+                `${technique.version_count} version${technique.version_count !== 1 ? "s" : ""}`,
+              );
+            }
+            parts.push(`Last updated ${updated}`);
+            return parts.join(" · ");
           })()}
         </div>
       </header>