Update pattern tests for new preset-based API

- Replace add() calls with edit() for preset creation
- Update tests to work with merged patterns.py
- Ensure all tests use new Preset object structure

test/patterns/on.py

@@ -14,13 +14,13 @@ def main():
     wdt = WDT(timeout=10000)
     
     # Create presets for on and off
-    p.add("test_on", {
+    p.edit("test_on", {
         "pattern": "on",
         "brightness": 64,
         "delay": 120,
         "colors": [(255, 0, 0), (0, 0, 255)]
     })
-    p.add("test_off", {"pattern": "off"})
+    p.edit("test_off", {"pattern": "off"})
 
     # ON phase
     p.select("test_on")