feat(fusion_accounting_reports): PDF export with QWeb template

Adds an AbstractModel report (report_pdf.py) and a single multi-purpose
QWeb template (report_pdf_template.xml) that renders P&L, Balance Sheet,
Trial Balance, and General Ledger results from the engine.

Wires the controller's /fusion/reports/export_pdf endpoint to actually
return base64-encoded PDF bytes via _render_qweb_pdf. The template walks
the result['rows'] list and applies indentation/bold based on level and
is_subtotal flags, with optional comparison columns when present.

Tests: 2 new (test_pdf_export.py) + 1 controller test updated to assert
the real PDF response. Net 109 -> 111.

Made-with: Cursor

fusion_accounting_reports/controllers/reports_controller.py

@@ -210,9 +210,25 @@ class FusionReportsController(http.Controller):
     @http.route('/fusion/reports/export_pdf', type='jsonrpc', auth='user')
     def export_pdf(self, report_type, date_from, date_to,
                    comparison='none', company_id=None):
+        Report = request.env['fusion.report']
+        report_def = Report.search([('report_type', '=', report_type)], limit=1)
+        if not report_def:
+            return {'status': 'error', 'message': f'No report definition for {report_type}'}
+        company_id = int(company_id) if company_id else request.env.company.id
+        pdf, _ct = request.env['ir.actions.report'].sudo()._render_qweb_pdf(
+            'fusion_accounting_reports.report_pdf_template',
+            res_ids=[report_def.id],
+            data={
+                'report_type': report_type,
+                'date_from': date_from, 'date_to': date_to,
+                'comparison': comparison, 'company_id': company_id,
+            },
+        )
+        import base64
         return {
-            'status': 'not_implemented',
-            'message': 'PDF export shipping in Task 34',
+            'status': 'ok',
+            'pdf_base64': base64.b64encode(pdf).decode('ascii'),
+            'filename': f'{report_type}_{date_from}_{date_to}.pdf',
         }
 
     @http.route('/fusion/reports/export_xlsx', type='jsonrpc', auth='user')