analytics: count a successful form as the FORM_SUCCESS Metrika goal

The counter was in place but nothing reached it: src/lib/lead.ts only pushed
a custom dataLayer event, which Metrika's ecommerce: 'dataLayer' ignores, so
form conversions were not counted at all.

All five forms — including the fitnes callback modal — funnel through the one
success branch in submitLead(), so a single ym(112352796, 'reachGoal',
'FORM_SUCCESS') per landing covers every one of them. The counter id is
hardcoded to match the inline snippet in index.html; two sources for it would
drift. The call is optional-chained and wrapped in try/catch, because losing
analytics must never cost a lead.

The honeypot is the one success that is not a conversion: the server answers
bots with 200 {ok:true, leadId:0} so they learn nothing, and leadId === 0 is
what keeps that answer out of the goal.

The goal itself still has to be created in the counter's settings as a
JavaScript event named FORM_SUCCESS — noted in deploy/README.md, replacing
the entry that said conversions were unwired.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

medcenterphysio/src/lib/lead.ts

@@ -9,6 +9,9 @@ import {
 const ENDPOINT = '/api/leads/medical-centers-existing-physio'
 const DRAFT_KEY = 'exo_medcenter_lead_draft'
 
+/** Тот же счётчик, что и в инлайн-снипете index.html — один на все четыре лендинга. */
+const METRIKA_ID = 112352796
+
 const FALLBACK_ERROR =
   'Не удалось отправить форму автоматически. Данные сохранены в браузере — свяжитесь с нами по +7 927 789-60-71.'
 
@@ -62,6 +65,8 @@ export async function submitLead(
 
     window.dataLayer = window.dataLayer ?? []
     window.dataLayer.push({ event: 'medcenter_lead_sent', form })
+    // leadId === 0 — ответ-обманка ханипота: сделки в amoCRM нет, конверсии тоже.
+    if (body.leadId !== 0) reachGoal('FORM_SUCCESS')
     localStorage.removeItem(DRAFT_KEY)
     return { ok: true }
   } catch (error) {
@@ -79,6 +84,20 @@ function saveDraft(payload: LeadInput) {
   }
 }
 
+/**
+ * Цель Метрики. `ym` объявляется синхронно инлайн-снипетом и до загрузки tag.js
+ * копит вызовы в очереди, так что ждать загрузки счётчика не нужно; опциональный
+ * вызов — страховка на случай блокировщика, вырезавшего снипет целиком.
+ */
+function reachGoal(goal: string) {
+  try {
+    window.ym?.(METRIKA_ID, 'reachGoal', goal)
+  } catch (error) {
+    // Аналитика не имеет права ломать отправку формы.
+    console.warn('Metrika reachGoal failed', error)
+  }
+}
+
 /* -------------------------------------------------------------------------- */
 /* Клик по кнопке звонка                                                       */
 /* -------------------------------------------------------------------------- */
@@ -152,5 +171,6 @@ export function reportCallClick(): void {
 declare global {
   interface Window {
     dataLayer?: Record<string, unknown>[]
+    ym?: (counterId: number, action: string, ...args: unknown[]) => void
   }
 }