feature: Tasks tab added for lab organizations. tasks now can be assigned and their status can be updated by the assignee.

backend/prisma/migrations/20260628190000_lab_task_assigned_at/migration.sql

@@ -0,0 +1,6 @@
+-- Track when a task was assigned (for sorting and display)
+
+ALTER TABLE "lab_case_tasks" ADD COLUMN "assignedAt" TIMESTAMP(3);
+
+CREATE INDEX "lab_case_tasks_assignedAt_labCaseId_priority_idx"
+  ON "lab_case_tasks"("assignedAt" DESC, "labCaseId" ASC, "priority" DESC);