feat(preview): respect blur mature content setting

tests/utils/test_preview_selection.py

@@ -0,0 +1,39 @@
+from py.utils.preview_selection import select_preview_media
+
+
+def test_select_preview_prefers_safe_media_when_blurred():
+    images = [
+        {"url": "nsfw", "type": "image", "nsfwLevel": 8},
+        {"url": "mid", "type": "image", "nsfwLevel": 4},
+        {"url": "safe", "type": "image", "nsfwLevel": 1},
+    ]
+
+    selected, level = select_preview_media(images, blur_mature_content=True)
+
+    assert selected["url"] == "safe"
+    assert level == 1
+
+
+def test_select_preview_returns_lowest_when_no_safe_media():
+    images = [
+        {"url": "x", "type": "image", "nsfwLevel": 16},
+        {"url": "r", "type": "image", "nsfwLevel": 4},
+        {"url": "xx", "type": "image", "nsfwLevel": 8},
+    ]
+
+    selected, level = select_preview_media(images, blur_mature_content=True)
+
+    assert selected["url"] == "r"
+    assert level == 4
+
+
+def test_select_preview_returns_first_when_blur_disabled():
+    images = [
+        {"url": "nsfw", "type": "image", "nsfwLevel": 32},
+        {"url": "safe", "type": "image", "nsfwLevel": 1},
+    ]
+
+    selected, level = select_preview_media(images, blur_mature_content=False)
+
+    assert selected["url"] == "nsfw"
+    assert level == 32