feat(fusion_accounting_l10n_ca): Canadian reports + tax return tracking

Replaces Enterprise's l10n_ca_reports with Fusion-native equivalents:
- ca_balance_sheet, ca_profit_loss as fusion.report definitions
- fusion.tax.return model for GST/HST/PST/T4/T5018 filing tracking
- Auto-installs when l10n_ca + fusion_accounting_reports both present

Removes Westin's last Canadian-compliance dependency on Enterprise's
account_reports.

Made-with: Cursor

fusion_accounting_l10n_ca/tests/__init__.py

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+from . import test_l10n_ca

fusion_accounting_l10n_ca/tests/test_l10n_ca.py

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+from datetime import date
+
+from odoo.tests import tagged
+from odoo.tests.common import TransactionCase
+
+
+@tagged("post_install", "-at_install")
+class TestL10nCa(TransactionCase):
+
+    def test_canadian_reports_seeded(self):
+        Report = self.env["fusion.report"].sudo()
+        ca_bs = Report.search([("code", "=", "ca_balance_sheet")], limit=1)
+        ca_pl = Report.search([("code", "=", "ca_profit_loss")], limit=1)
+        self.assertTrue(ca_bs, "ca_balance_sheet not seeded")
+        self.assertTrue(ca_pl, "ca_profit_loss not seeded")
+        self.assertEqual(ca_bs.report_type, "balance_sheet")
+        self.assertEqual(ca_pl.report_type, "pnl")
+
+    def test_canadian_pnl_runs_via_engine(self):
+        from odoo.addons.fusion_accounting_reports.services.date_periods import Period
+
+        period = Period(date(2025, 1, 1), date(2025, 12, 31), "FY 2025")
+        result = self.env["fusion.report.engine"].compute_pnl(
+            period, report_code="ca_profit_loss",
+        )
+        self.assertEqual(result["report_name"], "Profit and Loss (Canada)")
+        self.assertGreater(len(result["rows"]), 0)
+
+    def test_tax_return_create(self):
+        ret = self.env["fusion.tax.return"].create({
+            "return_type": "gst_hst",
+            "date_from": date(2025, 1, 1),
+            "date_to": date(2025, 3, 31),
+        })
+        self.assertNotEqual(ret.name, "New")
+        self.assertEqual(ret.state, "draft")