feat: add jpeg damage filter to fx

tests/test_fx_process.py

@@ -0,0 +1,37 @@
+from importlib.util import module_from_spec, spec_from_file_location
+from pathlib import Path
+
+import nonebot
+from PIL import Image
+
+
+nonebot.init()
+
+MODULE_PATH = Path(__file__).resolve().parents[1] / "konabot/plugins/fx_process/fx_handle.py"
+SPEC = spec_from_file_location("test_fx_handle_module", MODULE_PATH)
+assert SPEC is not None and SPEC.loader is not None
+fx_handle = module_from_spec(SPEC)
+SPEC.loader.exec_module(fx_handle)
+ImageFilterImplement = fx_handle.ImageFilterImplement
+
+
+def test_apply_jpeg_damage_keeps_size_and_rgba_mode():
+    image = Image.new("RGBA", (32, 24), (255, 0, 0, 128))
+
+    result = ImageFilterImplement.apply_jpeg_damage(image, 5)
+
+    assert result.size == image.size
+    assert result.mode == "RGBA"
+    assert result.getchannel("A").getextrema() == (128, 128)
+
+
+def test_apply_jpeg_damage_clamps_quality_range():
+    image = Image.new("RGB", (16, 16), (123, 222, 111))
+
+    low = ImageFilterImplement.apply_jpeg_damage(image, -10)
+    high = ImageFilterImplement.apply_jpeg_damage(image, 999)
+
+    assert low.size == image.size
+    assert high.size == image.size
+    assert low.mode == "RGBA"
+    assert high.mode == "RGBA"