purchase_advance_payment: fix fill amount button - rename, restyle, fix constraint

- Rename button "Fill amount" to "Pay order due amount" / "Plati dospjeli iznos ponude"
- Change button style from btn-link to btn-secondary for better visibility
- Fix @api.constrains to allow zero amount (prevents error on form save before action)
- Move positive amount validation to make_advance_payment method
- Update .pot and bs.po translations

🤖 assisted by claude

odoo-bringout-oca-purchase-workflow-purchase_advance_payment/purchase_advance_payment/i18n/bs.po

@@ -114,8 +114,8 @@ msgstr "Prikazani naziv"
 
 #. module: purchase_advance_payment
 #: model_terms:ir.ui.view,arch_db:purchase_advance_payment.view_account_voucher_wizard
-msgid "Fill amount"
-msgstr "Popuni iznos"
+msgid "Pay order due amount"
+msgstr "Plati dospjeli iznos ponude"
 
 #. module: purchase_advance_payment
 #: model:ir.model.fields,field_description:purchase_advance_payment.field_account_voucher_wizard_purchase__id

odoo-bringout-oca-purchase-workflow-purchase_advance_payment/purchase_advance_payment/i18n/purchase_advance_payment.pot

@@ -118,7 +118,7 @@ msgstr ""
 
 #. module: purchase_advance_payment
 #: model_terms:ir.ui.view,arch_db:purchase_advance_payment.view_account_voucher_wizard
-msgid "Fill amount"
+msgid "Pay order due amount"
 msgstr ""
 
 #. module: purchase_advance_payment

odoo-bringout-oca-purchase-workflow-purchase_advance_payment/purchase_advance_payment/wizard/purchase_advance_payment_wizard.py

@@ -85,7 +85,7 @@ class AccountVoucherWizardPurchase(models.TransientModel):
 
     @api.constrains("amount_advance")
     def check_amount(self):
-        if self.journal_currency_id.compare_amounts(self.amount_advance, 0.0) <= 0:
+        if self.journal_currency_id.compare_amounts(self.amount_advance, 0.0) < 0:
             raise exceptions.ValidationError(_("Amount of advance must be positive."))
         if self.env.context.get("active_id", False):
             if (
@@ -180,6 +180,8 @@ class AccountVoucherWizardPurchase(models.TransientModel):
     def make_advance_payment(self):
         """Create customer paylines and validates the payment"""
         self.ensure_one()
+        if self.journal_currency_id.compare_amounts(self.amount_advance, 0.0) <= 0:
+            raise exceptions.ValidationError(_("Amount of advance must be positive."))
         payment_obj = self.env["account.payment"]
         purchase_obj = self.env["purchase.order"]
 

odoo-bringout-oca-purchase-workflow-purchase_advance_payment/purchase_advance_payment/wizard/purchase_advance_payment_wizard_view.xml

@@ -24,9 +24,9 @@
                         <field name="amount_total" string="Order Due Amount" />
                         <button
                             name="action_fill_amount"
-                            string="Fill amount"
+                            string="Pay order due amount"
                             type="object"
-                            class="btn-link"
+                            class="btn-secondary"
                         />
                         <field name="currency_id" invisible="1" />
                     </group>