Moved from “SUSI plugin” to interpretation plugin:
• Per-room interpreter choice (none / susi, registry-ready for more)
• Event-level credentials shared across rooms
• Room-level enable + session state
• Backend abstraction in interpretation/backends.
BUG fixes, reworks:
• Test/disconnect use stored credentials, not empty POST
• Save won't wipe stored SUSI URL on blank URL field
• Interpreter selectable before sign-in
• Removed caption languages + stream URL override from commons
• ui styling on hero/table header
• Added tests/test_susi_credentials.py
etc….