feat: implement automation module

- Event-based triggers (Phase 1):
  - Trigger/TriggerLog models with field_change type
  - TriggerService for condition evaluation and action execution
  - Trigger CRUD API endpoints
  - Task integration (status, assignee, priority changes)
  - Frontend: TriggerList, TriggerForm components

- Weekly reports (Phase 2):
  - ScheduledReport/ReportHistory models
  - ReportService for stats generation
  - APScheduler for Friday 16:00 job
  - Report preview/generate/history API
  - Frontend: WeeklyReportPreview, ReportHistory components

- Tests: 23 new tests (14 triggers + 9 reports)
- OpenSpec: add-automation change archived

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/models/__init__.py

@@ -14,10 +14,16 @@ from app.models.audit_log import AuditLog, AuditAction, SensitivityLevel, EVENT_
 from app.models.audit_alert import AuditAlert
 from app.models.attachment import Attachment
 from app.models.attachment_version import AttachmentVersion
+from app.models.trigger import Trigger, TriggerType
+from app.models.trigger_log import TriggerLog, TriggerLogStatus
+from app.models.scheduled_report import ScheduledReport, ReportType
+from app.models.report_history import ReportHistory, ReportHistoryStatus
 
 __all__ = [
     "User", "Role", "Department", "Space", "Project", "TaskStatus", "Task", "WorkloadSnapshot",
     "Comment", "Mention", "Notification", "Blocker",
     "AuditLog", "AuditAlert", "AuditAction", "SensitivityLevel", "EVENT_SENSITIVITY", "ALERT_EVENTS",
-    "Attachment", "AttachmentVersion"
+    "Attachment", "AttachmentVersion",
+    "Trigger", "TriggerType", "TriggerLog", "TriggerLogStatus",
+    "ScheduledReport", "ReportType", "ReportHistory", "ReportHistoryStatus"
 ]