feat: auto-create guest in CRM on booking creation

- Add upsertGuestFromBooking() service — creates or updates guest record
  when a booking is made (matches by email/phone, creates if not found)
- Integrated into bookings.ts (manual PMS bookings) and publicWidget.ts
  (online widget bookings)
- Name parsed as Russian format: "Фамилия Имя [Отчество]"
- Non-throwing: booking creation never fails due to guest upsert errors

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/services/guestUpsert.ts

@@ -0,0 +1,105 @@
+import { db } from '../db'
+
+/**
+ * Parse a full name string (Russian format: "Фамилия Имя [Отчество]")
+ * into first_name, last_name, middle_name parts.
+ */
+function parseName(fullName: string): { firstName: string; lastName: string; middleName: string | null } {
+  const parts = fullName.trim().split(/\s+/)
+  if (parts.length === 1) {
+    return { firstName: parts[0], lastName: '', middleName: null }
+  }
+  return {
+    lastName:   parts[0],
+    firstName:  parts[1],
+    middleName: parts[2] ?? null,
+  }
+}
+
+/**
+ * Create or update a guest record based on booking data.
+ * - Matches existing guest by email OR phone (same hotel)
+ * - If found: updates name/phone/email if they were empty
+ * - If not found: creates new guest record
+ * Non-throwing: errors are swallowed so booking creation is never blocked.
+ */
+export async function upsertGuestFromBooking(params: {
+  hotelId: string
+  guestName: string
+  guestEmail?: string | null
+  guestPhone?: string | null
+}): Promise<void> {
+  try {
+    const { hotelId, guestName, guestEmail, guestPhone } = params
+
+    if (!guestName?.trim()) return
+
+    // Build match conditions
+    const conditions: string[] = []
+    const matchParams: unknown[] = [hotelId]
+    if (guestEmail?.trim()) {
+      matchParams.push(guestEmail.toLowerCase().trim())
+      conditions.push(`LOWER(email) = $${matchParams.length}`)
+    }
+    if (guestPhone?.trim()) {
+      const cleanPhone = guestPhone.replace(/\D/g, '')
+      if (cleanPhone.length >= 7) {
+        matchParams.push(cleanPhone)
+        conditions.push(`REGEXP_REPLACE(phone, '[^0-9]', '', 'g') = $${matchParams.length}`)
+      }
+    }
+
+    if (conditions.length > 0) {
+      // Check if guest already exists
+      const { rows } = await db.query(
+        `SELECT id, first_name, last_name, email, phone
+           FROM guests
+          WHERE hotel_id = $1 AND (${conditions.join(' OR ')})
+          ORDER BY updated_at DESC
+          LIMIT 1`,
+        matchParams,
+      )
+
+      if (rows[0]) {
+        // Guest exists — fill in any blank fields
+        const updates: string[] = []
+        const upParams: unknown[] = []
+        const g = rows[0]
+
+        if ((!g.email || g.email === '') && guestEmail?.trim()) {
+          upParams.push(guestEmail.toLowerCase().trim())
+          updates.push(`email = $${upParams.length}`)
+        }
+        if ((!g.phone || g.phone === '') && guestPhone?.trim()) {
+          upParams.push(guestPhone.trim())
+          updates.push(`phone = $${upParams.length}`)
+        }
+        if (updates.length > 0) {
+          upParams.push(rows[0].id)
+          await db.query(
+            `UPDATE guests SET ${updates.join(', ')}, updated_at = NOW() WHERE id = $${upParams.length}`,
+            upParams,
+          )
+        }
+        return
+      }
+    }
+
+    // No existing guest found — create new
+    const { firstName, lastName, middleName } = parseName(guestName)
+    await db.query(
+      `INSERT INTO guests (hotel_id, first_name, last_name, middle_name, email, phone)
+       VALUES ($1, $2, $3, $4, $5, $6)`,
+      [
+        hotelId,
+        firstName,
+        lastName,
+        middleName,
+        guestEmail?.toLowerCase().trim() ?? null,
+        guestPhone?.trim() ?? null,
+      ],
+    )
+  } catch {
+    // Non-critical — never block booking creation
+  }
+}