🧪 Add unit test for hash_token function

Adds a specific unit test `test_hash_token_known_value` to `tests/test_api_tokens.py` to assert that the `hash_token` pure function accurately computes the expected PBKDF2 digest for a known input string. This provides a hard check against any accidental regressions to the cryptographic hashing logic, iteration counts, or salt values used.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_api_tokens.py

@@ -554,3 +554,13 @@ class TestTokenUtils:
         # All characters should be valid lowercase hex digits.
         int(h, 16)
         assert h == h.lower()
+
+    @pytest.mark.unit
+    def test_hash_token_known_value(self):
+        """hash_token should return the exact expected PBKDF2 digest for a known input."""
+        from app.api.api_tokens import hash_token
+
+        # PBKDF2-HMAC-SHA256 with 100,000 iterations and salt b"api-token-v1"
+        token = "de_test_token_value"
+        expected_hash = "9b89d9adf2f390c75bf2fd0ff2bb5622ef5a9dce438354cce6e39f2f5401129e"
+        assert hash_token(token) == expected_hash