feat: activity assignment + team view for owner/admin

db: activities.assigneeId column (string, optional)

activity-actions: assigneeId saved on create (default: self), cleared on update
validation: assigneeId added to activitySchema
schema: assigneeId field on Activity type

activity-form-sheet: Atanan Kişi dropdown for owner/admin with member list
activity-team-view: new component — activities grouped by assignee,
  completion/edit/delete actions, overdue indicator, member avatars
activities-client: Ekip tab (owner/admin only), members + currentUserId props
activities page: fetches team memberships + user details, passes to client
activity-email-actions: filter by assigneeId ?? createdBy for both me/team modes

src/lib/appwrite/activity-email-actions.ts

@@ -53,7 +53,9 @@ export async function sendDailySummaryAction(
   });
 
   if (target === "me") {
-    const mine = todayActivities.filter((a) => a.createdBy === ctx.user.id);
+    const mine = todayActivities.filter(
+      (a) => (a.assigneeId ?? a.createdBy) === ctx.user.id,
+    );
     if (mine.length === 0) {
       return { ok: false, error: "Bugün için planlanmış aktiviteniz bulunmuyor." };
     }
@@ -75,7 +77,9 @@ export async function sendDailySummaryAction(
   for (const m of membershipsResult.memberships) {
     if (!m.userId || !m.confirm) continue;
 
-    const memberActivities = todayActivities.filter((a) => a.createdBy === m.userId);
+    const memberActivities = todayActivities.filter(
+      (a) => (a.assigneeId ?? a.createdBy) === m.userId,
+    );
     if (memberActivities.length === 0) continue;
 
     const member = await users.get(m.userId).catch(() => null);