feat(ui): restructure lead forms, self-serve Buy Credits, dialog blur

Revised lead-capture surfaces and credits bar:

- Dialog overlay gains backdrop blur (bg-black/60 backdrop-blur-sm).
- Shared primitives: LeadModalShell (icon/eyebrow header, scrollable body,
  sticky footer, trust-line slot), PhoneField (react-international-phone,
  dark, E.164 out), FormTrustLine ("Average response: under 10 minutes...").
- HireExpertModal: Name, Company, Job title, agent goal, Phone (required),
  monthly volume. EnterpriseModal: + work email (required logged-out),
  conditional deployment (yes/no/maybe, source-gated), agent goal.
  OnboardingModal: drop useCase. Phone mandatory except onboarding.
- Volume buckets match the backend qualifier (0-5k/5k-100k/100k+/not-sure).
- Delete TopUpModal; DograhCreditsCard now self-serve Buy Credits (amount
  chips $5/$10/$25/$50/$100 + custom min $5 → startTopUp seam) + Hire an
  Expert + dashed custom-pricing link opening Enterprise (billing_custom_pricing).
- PostHog events: drop topup_*, add buy_credits_clicked,
  buy_credits_amount_selected, custom_pricing_clicked. LeadFormsContext
  drops topup; LeadKind/LeadSource updated.
- Introduce a single --cta warm accent token (CTAs + focus rings only).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ui/src/components/lead-forms/submitLead.ts

@@ -1,15 +1,16 @@
 // Single submission seam for all lead forms.
-// Today: fires a PostHog capture. Later: add a POST to the backend
-// (MongoDB) endpoint here — no form component will need to change.
+// Fires a PostHog capture, and (when a token is supplied) POSTs to the separate
+// user_onboarding service. The service call is best-effort — PostHog is the
+// durable record and the user is never blocked if the service is down.
 
 import posthog from "posthog-js";
 
 import { PostHogEvent } from "@/constants/posthog-events";
 
 import type { LeadKind, LeadSource } from "./leadFieldOptions";
+import { postLeadToService } from "./onboardingServiceClient";
 
 const SUBMIT_EVENT: Record<LeadKind, string> = {
-  topup: PostHogEvent.TOPUP_REQUESTED,
   hire_expert: PostHogEvent.HIRE_EXPERT_SUBMITTED,
   enterprise: PostHogEvent.ENTERPRISE_LEAD_SUBMITTED,
 };
@@ -19,13 +20,16 @@ export interface SubmitLeadArgs {
   source: LeadSource;
   // Field values, already validated by the caller. Non-sensitive lead data.
   payload: Record<string, unknown>;
+  // Dograh auth token; when present the lead is also persisted to the service.
+  token?: string;
 }
 
-export async function submitLead({ kind, source, payload }: SubmitLeadArgs): Promise<void> {
-  // PostHog capture — the durable record until the backend endpoint lands.
+export async function submitLead({ kind, source, payload, token }: SubmitLeadArgs): Promise<void> {
+  // PostHog capture — the durable record, always fired.
   posthog.capture(SUBMIT_EVENT[kind], { source, ...payload });
 
-  // FUTURE: when the MongoDB endpoint exists, POST here, e.g.
-  //   const res = await submitLeadApiV1LeadsPost({ body: { kind, source, ...payload } });
-  //   if (res.error) throw new Error(detailFromError(res.error, "Failed to submit"));
+  // Persist to the separate user_onboarding service (best-effort).
+  if (token) {
+    await postLeadToService(kind, token, { source, ...payload });
+  }
 }