Added 60dB integration

[manishEMS47]

What we added (60db streaming STT):

• New 60db provider that transcribes live over its STT WebSocket (wss://api.60db.ai/ws/stt), running concurrently alongside Soniox.
• Audio fan-out fix so Soniox and 60db each get a full copy of the mic audio (one queue per streaming provider).
• New transcribe_audio_stream_60db() function; launch-on-press / stop-on-release wiring; an enum-lookup bug fix; tolerant key
  loading.
• websocket-client added to requirements; README updated.

How to use it:

1. pip install -r requirements.txt, then python main.py.
2. Select Active Providers → tick 60db (keep Soniox ticked to compare).
3. Paste your 60db API key into the 60db row (saved as sixtydb_key).
4. Optionally pick 60db as main provider (its text is what gets pasted).
5. Hold hotkey (ctrl+alt+x), speak, release — 60db transcribes live in its row.