Build and upload the sheet-per-scenario export workbook 🟩

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

orchestration/scenario_export_orchestrator.py

@@ -16,6 +16,7 @@ from dataclasses import dataclass
 from typing import Protocol, Sequence
 
 from domain.scenario_export.scenario_sheet import (
+    ExportSheet,
     PropertyScenarioData,
     shape_scenario_sheet,
 )
@@ -78,4 +79,26 @@ class ScenarioExportOrchestrator:
         recipient_email: str,
         export_name: str,
     ) -> ScenarioExportResult:
-        raise NotImplementedError
+        named_sheets: list[tuple[str, ExportSheet]] = []
+        row_count = 0
+        for scenario_id in scenario_ids:
+            rows = self._rows.rows_for(
+                portfolio_id=portfolio_id,
+                scenario_id=scenario_id,
+                property_ids=property_ids,
+            )
+            sheet = shape_scenario_sheet(rows)
+            named_sheets.append((self._scenarios.name_for(scenario_id), sheet))
+            row_count += len(sheet.rows)
+
+        data = render_workbook(named_sheets)
+        key = f"{self._key_prefix}/{export_name}.xlsx"
+        self._exports.put_object(key, data)
+        url = self._exports.generate_presigned_url(key, self._url_ttl_seconds)
+
+        return ScenarioExportResult(
+            presigned_url=url,
+            export_s3_key=key,
+            sheet_count=len(named_sheets),
+            row_count=row_count,
+        )