PoC: feed the migrated Symfony dashboard with real KPI and traffic-source data

[nicosomb]

Questions	Answers
Description?	Adds hookDisplayAdminDashboardZoneOne(), the modern counterpart of hookDashboardZoneOne(), so this module also feeds the migrated (Symfony) Back Office Dashboard. Reuses hookDashboardData() as-is (KPI values + traffic-source chart, real or simulated alike) instead of duplicating queries, and serializes the chart as a plain Chart.js config following the contract from PrestaShop/PrestaShop#42431; KPIs are rendered as plain server-side Twig, no JS needed. Legacy hooks are untouched. Version bumped 2.1.2 → 2.2.0 (minor, backward compatible with 8.2.0+).
Type?	new feature
BC breaks?	no
Deprecations?	no
Fixed ticket?	Fixes PrestaShop/PrestaShop#41971.
How to test?	1. On a shop with PrestaShop/PrestaShop#42431 and the dashboard feature flag enabled, install/reset this module. 2. Open the BO Dashboard: a KPI card and a traffic-sources doughnut chart render in Zone One.

Draft PoC for the #41971 spike — the only module of the four covering both a chart and plain KPI values.

[ps-jarvis]

This pull request seems to contain new translation strings. I have summarized them below to ease up review:

• Admin.Orderscustomers.Notification
  • Traffic sources

(Note: this is an automated message, but answering it will reach a real human)