feat!: generic defaults, dashboard fallback, PV filter fix (v1.3.0)

- Replace all hardcoded Tianpu/天普 defaults with generic "EMS Platform"
- Add energy_today fallback: query raw energy_data when daily summary empty
- Fix PV device filter to include sungrow_inverter device type
- Update APP_NAME, CUSTOMER default, SECRET_KEY, SMTP, Celery, email templates

BREAKING: CUSTOMER default changed from "tianpu" to "default"
Existing deployments with CUSTOMER=tianpu in .env are unaffected.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/services/report_scheduler.py

@@ -103,10 +103,10 @@ async def _run_report_task(task_id: int):
             recipients = task.recipients or []
             if isinstance(recipients, list) and recipients:
                 report_name = task.name or template.name
-                subject = f"{report_name} - 天普EMS自动报表"
+                subject = f"{report_name} - EMS Auto Report"
                 body_html = f"""
                 <div style="font-family: 'Microsoft YaHei', sans-serif; padding: 20px;">
-                    <h2 style="color: #1a73e8;">天普零碳园区智慧能源管理平台</h2>
+                    <h2 style="color: #1a73e8;">Smart Energy Management Platform</h2>
                     <p>您好，</p>
                     <p>系统已自动生成 <strong>{report_name}</strong>，请查收附件。</p>
                     <p style="color: #666; font-size: 13px;">