Note: this PR is a forward of https://github.com/odoo/enterprise/pull/96130

Implement the Belgian Registered Cash Register (Caisse Enregistreuse Certifiée) v2 specification as required by FPS Finance for certified POS restaurant systems.

The implementation is split into a core module and five bridge modules:

l10n_be_pos_blackbox (main module):
- FDM (Fiscal Data Module) communication layer that signs every fiscal event by sending a structured message to the blackbox device and receiving a hash + VSC counter in return. M110 (sale), M111 (refund), M112 (partial refund), M121 (order), M122 (cost-centre change), M123 (pre-bill), M130 (money in/out), M131 (drawer open), M140/M141 (work in/out), M150 (invoice), M160 (copy), M180/M181 (X/Z turnover report), M182/M183 (user X/Z report), UC230 (sale correction). M160 (copy), M180/M181 (X/Z turnover report), M182/M183 (user X/Z report), UC230 (sale correction).
- Input generator that encodes all line-level fiscal data (PLU hash, VAT groups, price rounding, grouping IDs) according to the spec.
- Fiscal receipt template (XML) that renders the blackbox hash, VSC counter, POS system identifier, and event sequence number on every printed receipt.
- X/Z daily report views with fiscal totals per VAT category.
- Training-mode support: activates the FDM training flag so the device does not count test transactions.
- Inspect popup (debug) for examining raw FDM messages.
- Error/warning popup system with traceback messages from the device.
- LocalStorage queue to replay pending mutations after a network outage.
- pos_config / pos_session overrides: enforce blackbox constraints (only EUR, no rounding, mandatory restaurant mode, etc.), manage device pairing, and accumulate per-session fiscal counters.
- Extensive unit-test suite: >6 000 lines covering the input generator's grouping-ID logic, price-consistency rules, and every mutation type against golden JSON fixtures.
- Browser tour tests (oracle + regression tours).

l10n_be_pos_blackbox_hr:
- Clock-in / clock-out flows for employees trigger M140/M141 work in/out mutations; employee INSZ/NISS number is required and stored on hr.employee; pos_session accumulates per-employee work records.

l10n_be_pos_blackbox_loyalty:
- Gift-card and discount reward lines are mapped to the correct MPV fiscal codes (UC260/UC261); loyalty products are flagged so the input generator can calculate their contribution to the signed total correctly.

l10n_be_pos_blackbox_self_order:
- Intercepts self-order confirmation on kiosk screens to sign the order with the FDM before the confirmation page is shown; adds a controller to expose the required blackbox data to the kiosk frontend.

l10n_be_pos_blackbox_settle_due:
- Handles the "settle due" payment flow: products used to represent deferred payments are flagged and treated as zero-VAT lines in the signed message.

l10n_be_pos_blackbox_urban_piper:
- Patches the Urban Piper ticket-screen and pos_store so that online orders routed through Urban Piper are also signed before finalisation.

community PR: https://github.com/odoo/odoo/pull/272155

task-id: 5864870