Add presets system and convert back to Flask

- Convert from Microdot back to Flask
- Add presets system with CRUD operations
- Store presets in presets.json file
- Replace patterns section with presets grid
- Add preset editor with full configuration
- Add collapse/expand functionality to left panel
- Always show on/off presets in presets list
- Highlight active preset matching current tab settings
- Add 'Create from Current' button in preset editor

Pipfile

@@ -12,8 +12,7 @@ python-rtmidi = "*"
 pyaudio = "*"
 aubio = "*"
 websocket-client = "*"
-flask = "*"
-flask-cors = "*"
+microdot = "*"
 
 [dev-packages]