Add configurable data retention: auto-anonymization of inactive customers

[guillaumeArgiles]

Description

This PR adds configurable data retention to the official GDPR module: an opt-in job that anonymizes customers who have been inactive beyond a merchant-defined period, to enforce the GDPR storage-limitation principle (art. 5.1.e). Today the module handles data rights on request (access, export, erasure) but never enforces a retention duration, which the CNIL recommends automating.

Disabled by default — nothing is ever anonymized unless a merchant explicitly enables it and sets a period.

What it does

• Detection — CustomerRepository::findInactiveCustomers(): a customer is "inactive" when the most recent of (last connection, last valid order) is older than the configured period.
• Two phases in DataRetentionService:
  1. Warn — email the customer (with a re-login link) and start a grace window; logging back in resets the inactivity.
  2. Anonymize — after the grace window, anonymize via the existing CustomerService primitive, so orders/invoices are preserved for legal accounting retention (Code de commerce art. L123-22, LPF art. L102 B) while personal data is anonymized.
• Scheduling — a console command php bin/console psgdpr:data-retention:run (with a --dry-run preview that sends/changes nothing), plus the actionCronJob hook for the ps_cronjobs module. No public endpoint.
• Back office — a new "Data retention" tab (enable switch, inactivity period, warning lead time).
• Emails — bilingual FR/EN warning templates, sent in the customer's language.
• Audit — every warning and anonymization is recorded in psgdpr_log.

Open question for maintainers

The retention job relies on the existing CustomerService::deleteCustomerDataFromPrestashop() (which uses DeleteCustomerCommand). Could a maintainer confirm the intended behavior of that command on orders and invoices (preserved vs. detached vs. removed)? The feature assumes the active → intermediate-archive → deletion model (anonymize the person, keep legally-required accounting records); I'd like to align on this before considering it final.

Test plan

1. Install the module, open Configure → Data retention, enable it, set a short inactivity period.
2. Preview safely: php bin/console psgdpr:data-retention:run --dry-run → reports how many customers would be warned/anonymized, sending and changing nothing.
3. Run for real: php bin/console psgdpr:data-retention:run → inactive customers receive the warning email; entries appear in psgdpr_log.
4. After the grace window, a subsequent run anonymizes still-inactive warned customers; orders/invoices remain.

Notes

• Compatible with PrestaShop 8 and 9; PHP syntax kept compatible down to the module's platform (7.2 lint), PHPStan level 5.
• No module version bump (left to the release process).

[ps-jarvis]

Hello @guillaumeArgiles!

This is your first pull request on psgdpr repository of the PrestaShop project.

Thank you, and welcome to this Open Source community!

[Progi1984]

@guillaumeArgiles Please use the PR table in description.