feat(calendar): update Event model and patch caldav.create_event with uid param

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

src/fabledassistant/models/event.py

@@ -24,6 +24,8 @@ class Event(Base):
     all_day: Mapped[bool] = mapped_column(Boolean, default=False)
     description: Mapped[str] = mapped_column(Text, default="")
     location: Mapped[str] = mapped_column(Text, default="")
+    caldav_uid: Mapped[str] = mapped_column(Text, default="")
+    color: Mapped[str] = mapped_column(Text, default="")
     recurrence: Mapped[str | None] = mapped_column(Text, nullable=True)
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
@@ -37,7 +39,9 @@ class Event(Base):
     def to_dict(self) -> dict:
         return {
             "id": self.id,
+            "user_id": self.user_id,
             "uid": self.uid,
+            "caldav_uid": self.caldav_uid,
             "project_id": self.project_id,
             "title": self.title,
             "start_dt": self.start_dt.isoformat() if self.start_dt else None,
@@ -45,7 +49,8 @@ class Event(Base):
             "all_day": self.all_day,
             "description": self.description,
             "location": self.location,
+            "color": self.color,
             "recurrence": self.recurrence,
-            "created_at": self.created_at.isoformat(),
-            "updated_at": self.updated_at.isoformat(),
+            "created_at": self.created_at.isoformat() if self.created_at else None,
+            "updated_at": self.updated_at.isoformat() if self.updated_at else None,
         }