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>

VERSIONS.json

@@ -1,6 +1,6 @@
 {
   "project": "ems-core",
-  "project_version": "1.2.0",
+  "project_version": "1.3.0",
   "last_updated": "2026-04-06",
-  "notes": "Backend-only architecture, frontend removed to customer repos"
+  "notes": "Generic defaults, dashboard energy fallback, PV device type filter fix"
 }