Add strike events to activity log

Record a StrikeEvent row whenever a strike is added or removed,
and surface them in the activity log timeline with timestamp,
child name, and whether the strike was added or removed.

- New strike_events table (auto-created on startup)
- children router records prev/new strikes on every update
- GET /api/logs/strikes and DELETE /api/logs/strikes/:id endpoints
- Log view merges strike entries into the timeline (red dot,
  "✕ Strike added (2/3)" / "↩ Strike removed (1/3)")

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/models/__init__.py

@@ -6,6 +6,7 @@ from app.models.subject import Subject, SubjectOption
 from app.models.schedule import ScheduleTemplate, ScheduleBlock
 from app.models.session import DailySession, TimerEvent, TimerEventType
 from app.models.activity import ActivityLog
+from app.models.strike import StrikeEvent
 
 __all__ = [
     "Base",
@@ -20,4 +21,5 @@ __all__ = [
     "TimerEvent",
     "TimerEventType",
     "ActivityLog",
+    "StrikeEvent",
 ]

backend/app/models/strike.py

@@ -0,0 +1,18 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, Integer, func
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.models.base import Base
+
+
+class StrikeEvent(Base):
+    __tablename__ = "strike_events"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    child_id: Mapped[int] = mapped_column(ForeignKey("children.id", ondelete="CASCADE"), nullable=False)
+    occurred_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), nullable=False)
+    prev_strikes: Mapped[int] = mapped_column(Integer, nullable=False)
+    new_strikes: Mapped[int] = mapped_column(Integer, nullable=False)
+
+    child: Mapped["Child"] = relationship("Child")  # noqa: F821

backend/app/routers/children.py

@@ -5,6 +5,7 @@ from sqlalchemy import select
 
 from app.dependencies import get_db, get_current_user
 from app.models.child import Child
+from app.models.strike import StrikeEvent
 from app.models.user import User
 from app.schemas.child import ChildCreate, ChildOut, ChildUpdate
 from app.websocket.manager import manager
@@ -89,7 +90,9 @@ async def update_strikes(
     child = result.scalar_one_or_none()
     if not child:
         raise HTTPException(status_code=404, detail="Child not found")
+    prev = child.strikes
     child.strikes = body.strikes
+    db.add(StrikeEvent(child_id=child.id, prev_strikes=prev, new_strikes=body.strikes))
     await db.commit()
     await db.refresh(child)
     await manager.broadcast(child_id, {"event": "strikes_update", "strikes": child.strikes})

backend/app/routers/logs.py

@@ -2,7 +2,7 @@ from datetime import date
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.ext.asyncio import AsyncSession
-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.orm import selectinload
 
 from app.dependencies import get_db, get_current_user
@@ -10,9 +10,10 @@ from app.models.activity import ActivityLog
 from app.models.child import Child
 from app.models.session import DailySession, TimerEvent
 from app.models.schedule import ScheduleBlock
+from app.models.strike import StrikeEvent
 from app.models.subject import Subject  # noqa: F401
 from app.models.user import User
-from app.schemas.activity import ActivityLogCreate, ActivityLogOut, ActivityLogUpdate, TimelineEventOut, TimelineEventUpdate
+from app.schemas.activity import ActivityLogCreate, ActivityLogOut, ActivityLogUpdate, StrikeEventOut, TimelineEventOut, TimelineEventUpdate
 
 router = APIRouter(prefix="/api/logs", tags=["logs"])
 
@@ -119,6 +120,59 @@ async def delete_timeline_event(
     await db.commit()
 
 
+@router.get("/strikes", response_model=list[StrikeEventOut])
+async def get_strike_events(
+    child_id: int | None = None,
+    log_date: date | None = None,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    query = (
+        select(StrikeEvent)
+        .join(Child, StrikeEvent.child_id == Child.id)
+        .where(Child.user_id == current_user.id)
+        .options(selectinload(StrikeEvent.child))
+        .order_by(StrikeEvent.occurred_at.desc())
+    )
+    if child_id:
+        query = query.where(StrikeEvent.child_id == child_id)
+    if log_date:
+        query = query.where(func.date(StrikeEvent.occurred_at) == log_date)
+
+    result = await db.execute(query)
+    events = result.scalars().all()
+    return [
+        StrikeEventOut(
+            id=e.id,
+            child_id=e.child_id,
+            child_name=e.child.name,
+            occurred_at=e.occurred_at,
+            log_date=e.occurred_at.date(),
+            prev_strikes=e.prev_strikes,
+            new_strikes=e.new_strikes,
+        )
+        for e in events
+    ]
+
+
+@router.delete("/strikes/{strike_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_strike_event(
+    strike_id: int,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    result = await db.execute(
+        select(StrikeEvent)
+        .join(Child, StrikeEvent.child_id == Child.id)
+        .where(StrikeEvent.id == strike_id, Child.user_id == current_user.id)
+    )
+    event = result.scalar_one_or_none()
+    if not event:
+        raise HTTPException(status_code=404, detail="Strike event not found")
+    await db.delete(event)
+    await db.commit()
+
+
 @router.get("", response_model=list[ActivityLogOut])
 async def list_logs(
     child_id: int | None = None,

backend/app/schemas/activity.py

@@ -1,5 +1,5 @@
 from datetime import date, datetime, timezone
-from pydantic import BaseModel, field_serializer
+from pydantic import BaseModel, computed_field, field_serializer
 
 
 class ActivityLogCreate(BaseModel):
@@ -51,3 +51,21 @@ class TimelineEventOut(BaseModel):
         if dt.tzinfo is None:
             dt = dt.replace(tzinfo=timezone.utc)
         return dt.isoformat()
+
+
+class StrikeEventOut(BaseModel):
+    id: int
+    child_id: int
+    child_name: str
+    occurred_at: datetime
+    log_date: date
+    prev_strikes: int
+    new_strikes: int
+
+    model_config = {"from_attributes": True}
+
+    @field_serializer("occurred_at")
+    def serialize_occurred_at(self, dt: datetime) -> str:
+        if dt.tzinfo is None:
+            dt = dt.replace(tzinfo=timezone.utc)
+        return dt.isoformat()