feat: add system settings, audit log, device detail, dark mode, i18n, email notifications

System Management:
- System Settings page with 8 configurable parameters (admin only)
- Audit Log page with filterable table (user, action, resource, date range)
- Audit logging wired into auth, devices, users, alarms, reports API handlers
- SystemSetting model + migration (002)

Device Detail:
- Dedicated /devices/:id page with 4 tabs (realtime, historical trends, alarm history, device info)
- ECharts historical charts with granularity/time range selectors
- Device name clickable in Devices and Monitoring tables → navigates to detail

Email & Scheduling:
- Email service with SMTP support (STARTTLS/SSL/plain)
- Alarm email notification with professional HTML template
- Report scheduler using APScheduler for cron-based auto-generation
- Scheduled report task seeded (daily at 8am)

UI Enhancements:
- Dark mode toggle (persisted to localStorage, Ant Design darkAlgorithm)
- Data comparison view in Analysis page (dual date range, side-by-side metrics)
- i18n framework (i18next) with zh/en translations for menu and common UI
- Language switcher in header (中文/English)

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

scripts/seed_data.py

@@ -14,7 +14,7 @@ from app.models.user import User, Role
 from app.models.device import Device, DeviceType, DeviceGroup
 from app.models.alarm import AlarmRule, AlarmEvent
 from app.models.carbon import EmissionFactor
-from app.models.report import ReportTemplate
+from app.models.report import ReportTemplate, ReportTask
 
 
 async def seed():
@@ -283,7 +283,8 @@ async def seed():
                 threshold=0.0,
                 duration=3600,
                 severity="critical",
-                notify_channels=["app", "sms", "wechat"],
+                notify_channels=["app", "sms", "wechat", "email"],
+                notify_targets={"emails": ["admin@tianpu.com", "energy@tianpu.com"]},
                 is_active=True,
             ),
             AlarmRule(
@@ -294,7 +295,8 @@ async def seed():
                 threshold=38.0,
                 duration=300,
                 severity="critical",
-                notify_channels=["app", "sms"],
+                notify_channels=["app", "sms", "email"],
+                notify_targets={"emails": ["admin@tianpu.com"]},
                 is_active=True,
             ),
             AlarmRule(
@@ -376,6 +378,24 @@ async def seed():
 
         await session.flush()
 
+        # =====================================================================
+        # 8b. 定时报表任务 (daily report at 8am)
+        # =====================================================================
+        report_tasks = [
+            ReportTask(
+                template_id=1,  # 日报模板
+                name="每日能源运行日报",
+                schedule="0 8 * * *",
+                recipients=["admin@tianpu.com"],
+                export_format="xlsx",
+                status="pending",
+                is_active=True,
+                created_by=1,
+            ),
+        ]
+        session.add_all(report_tasks)
+        await session.flush()
+
         # =====================================================================
         # 9. 历史告警事件 (15 events over last 7 days)
         # =====================================================================
@@ -545,6 +565,7 @@ async def seed():
         print(f"  - {len(alarm_rules)} alarm rules")
         print(f"  - {len(factors)} emission factors")
         print(f"  - {len(templates)} report templates")
+        print(f"  - {len(report_tasks)} report tasks (scheduled)")
         print(f"  - {len(alarm_events)} alarm events (historical)")
 
     await engine.dispose()