fix: add test data

Author: b-long

tests/integration/test_data/empty_file.txt

@@ -0,0 +1,5 @@
+Hello, World! This is a test text file for TDF target mode testing.
+It contains multiple lines to test various scenarios.
+Line 3 with special characters: àáâãäå
+Line 4 with numbers: 123456789
+Final line with punctuation: !@#$%^&*()_+

tests/integration/test_data/sample_binary.png

@@ -0,0 +1,4 @@
+Sensitive data with attributes.
+Classification: SECRET
+Department: Engineering
+Project: TDF Testing