Add Asset Management app

Assets from purchase invoice lines, straight-line depreciation/amortization with salvage value, disposals, and [Asset Mgmt] sources in Batch GL Entries. Green third workspace with an app access guard.

app/accounting/vat_report.php

@@ -139,6 +139,8 @@
     invoice: 'Invoice', credit_note: 'Credit Note',
     purchase_invoice: 'Purchase Invoice', supplier_credit_note: 'Supplier Credit Note',
     receipt: 'Receipt', payment: 'Payment', manual: 'Manual',
+    asset_capitalization: 'Asset Mgmt · Capitalization', asset_depreciation: 'Asset Mgmt · Depreciation',
+    asset_amortization: 'Asset Mgmt · Amortization', asset_disposal: 'Asset Mgmt · Disposal',
   };
 
   load_departments();