feat: cashier/counter reports, service-order & remission flows, Rached migration utils

- Add "Mis cortes de caja" report for cashiers/counters with sales detail.
- Cash register history scoped to own cuts for non-admin roles; new /register/<id>/sales endpoint.
- Remove dashboard from cashier menu; add Reports to cashier/counter.
- Service orders: assign mechanic, budget field, invoice flag, counter/cashier can add items/remissions, convert to remission.
- Remission notes module (UI, CSS, courier, counter remissions).
- Customer hard-delete and vehicle/customer linkage in workshop.
- POS: always show search results, compact payment grid, credit validation, tier pricing (5%/10%), ticket with customer/folio.
- Inventory: CSV template with sku_secondary, alias import.
- Rached migration scripts and DB migrations.
- Version-bump cached JS/CSS query strings.

Excludes local Rached session tokens/captures (rached_*.json / rached_*.txt).

pos/migrations/v4.20_cashier_sell_permissions.sql

@@ -0,0 +1,18 @@
+-- v4.20 — Ensure existing cashier employees can sell and view quotations.
+-- The cashier default set already includes these permissions, but employees
+-- created before the fix may be missing them.
+INSERT INTO employee_permissions (employee_id, permission)
+SELECT e.id, p.perm
+FROM employees e
+CROSS JOIN (VALUES
+    ('pos.sell'),
+    ('pos.discount'),
+    ('pos.cancel'),
+    ('pos.view')
+) AS p(perm)
+WHERE e.role = 'cashier'
+  AND e.is_active = true
+  AND NOT EXISTS (
+      SELECT 1 FROM employee_permissions ep
+      WHERE ep.employee_id = e.id AND ep.permission = p.perm
+  );