feat(hash): add SHA-256 hashing functionality

Add SHA-256-based hashing for files and store the values in a
dictionary for later use with the detection-and-deletion function.

duplicate_check.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 # Duplicate Check
-# Version: 0.8.0
+# Version: 0.9.0
 
 # Copyright 2025 Jake Winters
 # SPDX-License-Identifier: BSD-3-Clause
@@ -9,3 +9,11 @@
 
 import os
 import hashlib
+
+
+def hash_file(file_path):
+    sha256_hash = hashlib.sha256()
+    with open(file_path, 'rb') as f:
+        for byte_block in iter(lambda: f.read(65536), b''):
+            sha256_hash.update(byte_block)
+    return sha256_hash.hexdigest()