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/schemas/report.py

@@ -0,0 +1,50 @@
+from datetime import datetime
+from typing import Optional, List, Dict, Any
+from pydantic import BaseModel
+
+
+class ProjectSummary(BaseModel):
+    project_id: str
+    project_title: str
+    completed_count: int
+    in_progress_count: int
+    overdue_count: int
+    total_tasks: int
+
+
+class ReportSummary(BaseModel):
+    completed_count: int
+    in_progress_count: int
+    overdue_count: int
+    total_tasks: int
+
+
+class WeeklyReportContent(BaseModel):
+    week_start: str
+    week_end: str
+    generated_at: str
+    projects: List[Dict[str, Any]]
+    summary: ReportSummary
+
+
+class ReportHistoryItem(BaseModel):
+    id: str
+    report_id: str
+    generated_at: datetime
+    content: Dict[str, Any]
+    status: str
+    error_message: Optional[str] = None
+
+    class Config:
+        from_attributes = True
+
+
+class ReportHistoryListResponse(BaseModel):
+    reports: List[ReportHistoryItem]
+    total: int
+
+
+class GenerateReportResponse(BaseModel):
+    message: str
+    report_id: str
+    summary: ReportSummary