feat(package): session packages backed by a credit ledger

"Six laser sessions" is the common case in an aesthetics clinic: the patient
pays once and books the sessions later.

Credit is a ledger, not a counter. No table has a remaining/used_count column
and a schema test enforces that — the balance is always SUM(delta) over
append-only rows, so every number a patient sees has a full history behind it.
Corrections are new rows, never edits.

- purchase / consume / refund / adjustment / expiry, each with a reason, an
  author and the appointment it belongs to
- consume happens in confirm(), never in quote(): if the preview consumed, a
  page refresh would cost the patient a session
- cancelling adds a refund row; the consume row stays
- FIFO across a patient's packages — the oldest is closest to expiring
- an empty package is not an error, it just does not apply and the patient pays
- adjust/expire need a doctor or clinic role, and adjust always needs a reason
- app:package:expire writes the closing row so "where did my 3 sessions go?"
  always has an answer

Consume takes a pessimistic lock on the one package row. That is the opposite
of task 07's slot buckets, and docs/api/package.md carries the table explaining
why, so nobody unifies them later.

Idempotency checks for an existing consume row before inserting rather than
catching the unique violation: in Doctrine that exception closes the
EntityManager and burns the rest of the request. The unique key stays as the
last line of defence.

Admin: PackagesPage, a packages tab on the patient record, and a ledger page
whose running-balance column shows where the final number came from.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

assets/admin/App.tsx

@@ -75,6 +75,8 @@ import ClinicAppointmentSettingsPage from './pages/ClinicAppointmentSettingsPage
 import PatientsListPage from './pages/PatientsListPage';
 import InventoryPage from './pages/InventoryPage';
 import BranchesPage from './pages/BranchesPage';
+import PackagesPage from './pages/PackagesPage';
+import PatientPackageLedgerPage from './pages/PatientPackageLedgerPage';
 import PoliciesPage from './pages/PoliciesPage';
 import PolicyFormPage from './pages/PolicyFormPage';
 import PolicySimulationPage from './pages/PolicySimulationPage';
@@ -293,6 +295,8 @@ export default function App() {
         <Route path="policies" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><PoliciesPage /></RoleRoute>} />
         <Route path="policies/new" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'update']}><PolicyFormPage /></RoleRoute>} />
         <Route path="policies/:policyUuid/simulate" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><PolicySimulationPage /></RoleRoute>} />
+        <Route path="packages" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><PackagesPage /></RoleRoute>} />
+        <Route path="patient-package/:patientPackageUuid/ledger" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><PatientPackageLedgerPage /></RoleRoute>} />
         <Route path="resources" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><ResourcesPage /></RoleRoute>} />
         <Route path="resources/types" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><ResourceTypesPage /></RoleRoute>} />
         <Route path="resources/skills" element={<RoleRoute roles={['doctor', 'clinic', 'secretary']} blockClinicScope permission={['appointment_settings', 'view']}><SkillsPage /></RoleRoute>} />