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/weather_model.py

@@ -3,7 +3,7 @@
 Shared by both the real-time simulator and the backfill script.
 Deterministic when given a seed — call set_seed() for reproducible backfills.
 
-Tianpu campus: 39.9N, 116.4E (Beijing / Daxing district)
+Default campus: 39.9N, 116.4E (Beijing / Daxing district)
 """
 
 import math
@@ -87,7 +87,7 @@ def solar_altitude(dt: datetime) -> float:
 
     # Local solar time
     beijing_dt = dt + timedelta(hours=BEIJING_TZ_OFFSET) if dt.tzinfo else dt
-    # Standard meridian for UTC+8 is 120E; Tianpu is at 116.4E
+    # Standard meridian for UTC+8 is 120E; default campus is at 116.4E
     time_offset = _equation_of_time(doy) + 4 * (BEIJING_LON - 120.0)
     solar_hour = beijing_dt.hour + beijing_dt.minute / 60.0 + beijing_dt.second / 3600.0
     solar_hour += time_offset / 60.0