feat: Event archive management — Event model, migration, API, frontend page (Phase 8)

- Event ORM model with status/level enums, domain categories, review tracking
- Alembic migration e7f3a9b1c5d0 for events table
- Event crawler service with placeholder data (12 sample events)
- GET /api/v1/events with status/domain/search filtering and overdue_days
- EventArchivePage with filter toolbar (status, domain, search) and adaptive card grid
- Status badges, level badges, domain tags, overdue markers on event cards
- Loading/error/empty states, hover-to-honey card interaction

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

backend/app/api/events.py

@@ -0,0 +1,65 @@
+"""Events API — 事件档案列表，三维筛选。"""
+import logging
+from datetime import datetime, timezone
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.middleware.auth import require_auth
+from app.models.event import Event, EventStatus, DOMAINS
+from app.models.user import User
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/events", tags=["events"])
+
+
+@router.get("")
+async def list_events(
+    status: str | None = Query(None, description="按状态筛选"),
+    domain: str | None = Query(None, description="按领域筛选"),
+    search: str = Query("", description="按标题模糊搜索"),
+    _user: User = Depends(require_auth),
+    db: AsyncSession = Depends(get_db),
+):
+    """事件卡片列表，支持三维筛选。"""
+    stmt = select(Event).order_by(Event.occurred_date.desc())
+
+    valid_statuses = {s.value for s in EventStatus}
+    if status and status in valid_statuses:
+        stmt = stmt.where(Event.status == status)
+
+    if domain and domain in DOMAINS:
+        stmt = stmt.where(Event.domain == domain)
+
+    if search:
+        stmt = stmt.where(Event.title.ilike(f"%{search}%"))
+
+    result = await db.execute(stmt)
+    events = result.scalars().all()
+
+    now = datetime.now(timezone.utc)
+    data = []
+    for ev in events:
+        overdue_days = 0
+        if ev.next_review and ev.next_review < now:
+            overdue_days = (now - ev.next_review).days
+
+        data.append({
+            "id": ev.id,
+            "title": ev.title,
+            "level": ev.level.value,
+            "domain": ev.domain,
+            "status": ev.status.value,
+            "occurred_date": ev.occurred_date.isoformat(),
+            "last_reviewed": ev.last_reviewed.isoformat() if ev.last_reviewed else None,
+            "no_new_info_count": ev.no_new_info_count,
+            "next_review": ev.next_review.isoformat() if ev.next_review else None,
+            "overdue_days": overdue_days,
+            "created_at": ev.created_at.isoformat() if ev.created_at else None,
+            "updated_at": ev.updated_at.isoformat() if ev.updated_at else None,
+        })
+
+    return {"events": data}