feat(profile): add Danger zone account deletion UI

frontend/src/api/client.ts

@@ -106,6 +106,10 @@ export const api = {
   getProfile: () => request<Profile>("/api/profile"),
   updateProfile: (profile: Profile) =>
     request<Profile>("/api/profile", { method: "PUT", body: JSON.stringify(profile) }),
+  // Permanently deletes the signed-in user's entire account. The caller is
+  // responsible for following a successful call with a real logout
+  // navigation -- this does not touch the session cookie (see Profile.tsx).
+  deleteProfile: () => request<void>("/api/profile", { method: "DELETE" }),
 
   // Review queue -- cursor-paginated: pass the previous page's next_cursor
   // as `before` to fetch the next one. Fetching every activity's laps and