add JSON API endpoint support to prevent: Content Type Conversion

[ankitsejwal]

Pgweb only accepts form data, forcing us for JSON→form conversion

// Convert JSON body to form data for pgweb compatibility
  const formData = new URLSearchParams()
  Object.entries(req.body || {}).forEach(([key, value]) => {
    formData.append(key, String(value))
  })
  fetchOptions.body = formData.toString()
  fetchOptions.headers['Content-Type'] =
  'application/x-www-form-urlencoded'