add Pre and Post period checking

apps/kpi_analysis/trafic_analysis.py

@@ -290,6 +290,16 @@ if not all([two_g_file, three_g_file, lte_file]):
     st.info("Please upload all 3 reports and select the comparison periods.")
     st.stop()
 
+# Warning if pre and post periode are the same
+if pre_range == post_range:
+    st.warning("⚠️ Pre and post periode are the same.")
+    st.stop()
+
+# Warning if pre and post are overlapping
+if pre_range[0] < post_range[0] and pre_range[1] > post_range[1]:
+    st.warning("⚠️ Pre and post periode are overlapping.")
+    st.stop()
+
 if st.button("🔍 Run Analysis"):
 
     df_2g = read_uploaded_file(two_g_file)