Add dashexample module for the new Symfony dashboard hooks

[mattgoud]

Description

Adds a new example module, dashexample, that demonstrates how a module integrates with the migrated (Symfony) Back Office Dashboard through its new dedicated hook family.

It is both living documentation of the integration contract and a validation vehicle for the dashboard migration (core issue PrestaShop/PrestaShop#41968).

What it demonstrates

• Registering on the new dashboard hooks: displayAdminDashboardZoneOne, displayAdminDashboardZoneTwo, displayAdminDashboardToolbar.
• Rendering hook content through module Twig templates — no Smarty, no HelperForm, no Db::getInstance().
• Using hook parameters (date_from / date_to).
• Loading the module's own CSS/JS assets from its hook output — no actionAdminControllerSetMedia, no get_class($this->context->controller) detection.

The README.md explains the legacy-vs-Symfony hook families and how a single module can register on both to support multiple PrestaShop versions.

Requirements

• PrestaShop 9.2.0+ (introduces the migrated dashboard and its hooks).
• The dashboard feature flag enabled (Advanced Parameters > New & Experimental Features).

How to test

1. On a 9.2.0+ shop, enable the dashboard feature flag.
2. Install the module: php bin/console prestashop:module install dashexample.
3. Open the Dashboard: the module renders blocks in Zone One and Zone Two, plus a marker in the toolbar area, and its own CSS/JS are loaded.
4. Disable the flag: the legacy dashboard is unaffected (the module registers only the new hooks).

Related

• Core PR: Migrate Dashboard to Symfony behind a beta feature flag (initialization) PrestaShop#42077
• Core issue: Migration Dashboard - Initialiation PrestaShop#41968