style: fix spelling (British to American English)

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

app/utils/cache.py

@@ -1,7 +1,7 @@
 """
 Lightweight Redis caching layer for frequently accessed data.
 
-Provides a thin wrapper around Redis GET/SET with JSON serialisation and
+Provides a thin wrapper around Redis GET/SET with JSON serialization and
 configurable TTLs.  All operations are **fail-open**: if Redis is
 unavailable the caller simply gets a cache miss and falls back to the
 database or other source of truth.

docs/ConfigurationGuide.md

@@ -800,7 +800,7 @@ UI_DEFAULT_COLOR_SCHEME=dark
 
 ## Performance & Caching
 
-DocuElevate automatically optimises database access and uses Redis as a
+DocuElevate automatically optimizes database access and uses Redis as a
 caching layer for frequently accessed data.
 
 ### Database Indexes

tests/test_cache.py

@@ -50,7 +50,7 @@ def test_cache_get_returns_none_on_miss():
 
 @pytest.mark.unit
 def test_cache_get_returns_deserialized_value():
-    """cache_get should deserialise the stored JSON string."""
+    """cache_get should deserialize the stored JSON string."""
     mock_client = MagicMock()
     mock_client.get.return_value = json.dumps(["application/pdf", "image/png"])
     with patch("app.utils.cache._get_redis", return_value=mock_client):