feat(sticker): wire _qty_total in SO + Job External outers

Activates the per-box loop landed in the prior commit. SO External
reads line.product_uom_qty; Job External reads job.qty. Inner
template now renders one sticker per physical box, marking each
with "X / N" in the Qty row.

Verified on fp.job 2635 (qty temporarily set to 3): 3-page PDF
with Qty rows "1 / 3", "2 / 3", "3 / 3" — each page identical
otherwise (same WO#, same QR, same body fields).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_reports/__manifest__.py

@@ -3,7 +3,7 @@
 # License OPL-1 (Odoo Proprietary License v1.0)
 {
     'name': 'Fusion Plating — Reports',
-    'version': '19.0.10.12.0',
+    'version': '19.0.10.13.0',
     'category': 'Manufacturing/Plating',
     'summary': 'PDF reports for Fusion Plating: quote, SO, WO, packing, BoL, CoC, invoice, receipt, quality + compliance.',
     'depends': [