leads: new phone number and an amoCRM lead on every call-button click

The published number becomes +7 927 789-60-71 across all four landings —
`contacts` in each `src/data/content.ts`, plus the fallback messages in the
lead endpoints and `src/lib/lead.ts` that spell it out when amoCRM is down.
The `legacy/` reference pages keep the old number: they are the visual
originals, not something that ships.

Tapping the phone button now also creates a lead. It cannot reuse the form
path: a click carries no name and no number, so `callClickSchema` in
`shared/lead.ts` validates the tracking data alone, `LeadService.submitCallClick`
creates a contactless lead tagged `клик по телефону`, and `AmoClient.createLead`
takes an optional `contactId` for it. The mapper's field/note split moved into
`collect()` so both lead kinds share it.

The browser fires this with `sendBeacon` (falling back to `fetch keepalive`),
because the same click hands the page to `tel:` and a plain fetch would be
cut off mid-flight. Duplicates are held down from both ends: one lead per
browser session on the client, four per IP per 30 minutes on the server.

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

medcenterstart/shared/lead.ts

@@ -41,3 +41,26 @@ export type LeadInput = z.input<typeof leadSchema>
 export type LeadResponse =
   | { ok: true; leadId: number; contactId: number }
   | { ok: false; error: string; fields?: Record<string, string> }
+
+/* -------------------------------------------------------------------------- */
+/* Клик по кнопке звонка                                                       */
+/* -------------------------------------------------------------------------- */
+
+/**
+ * A visitor tapping the phone button leaves no contact details, so this shares
+ * nothing with `leadSchema` but the tracking data: it records where the click
+ * happened, and the lead it produces carries no contact at all.
+ */
+export const callClickSchema = z.object({
+  page: optionalText(300),
+  referrer: optionalText(500),
+  utm: z.partialRecord(z.enum(utmKeys), z.string().max(300)).optional(),
+  /** Honeypot. Bots fill it in; humans never see it. */
+  website: z.string().max(200).optional(),
+})
+
+export type CallClickPayload = z.infer<typeof callClickSchema>
+/** What the client sends — before zod's optional/empty-string normalisation. */
+export type CallClickInput = z.input<typeof callClickSchema>
+
+export type CallClickResponse = { ok: true; leadId: number } | { ok: false; error: string }