Unify session action button styles: same padding, delete in red

- Add .session-copy CSS (was unstyled — browser default)
- .session-download/.session-copy: neutral gray, same padding 4px 12px
- .session-delete: red (--danger) instead of accent
- Bump 1.22.8, SW cache v39->v40

simtrace2_pysniff/__init__.py

@@ -6,7 +6,7 @@ from .gsmtap import GsmtapSender, GsmtapReceiver
 from .pcap import PcapWriter
 from .dump import FileDumper, format_message
 
-__version__ = '1.22.7'
+__version__ = '1.22.8'
 __all__ = [
     'SniffSession',
     'DeviceDisconnected',