Session GUI: disconnect detection, self-contained stream polling, UI polish, angle target selector, auto-increment sessions

- EMG/IMU stale detection (1s threshold) with visual feedback
- Sync block yellow until all inputs connected
- Removed _check_lsl from poll loop; angle/marker streams self-contained
- Lightened dark palette, narrowed EMG/IMU panels, Live Metrics fills width
- Console output panel, reduced flow block heights, removed LSL hint
- 50ms poll timer (20Hz) with throttled LSL resolves (0.25s)
- Rate shows N/A when no data present
- Hand tracking 2s stale-to-disconnect timeout
- Default target angles: full14 (all 14 joints) with UI combo selector
- Auto-increment session number on startup and after each save

Author: Jshulgach

examples/joint_angle_regression/lsl_utils.py

@@ -47,7 +47,7 @@
     "index_only": ["index_mcp", "index_pip", "index_dip"],
 }
 
-DEFAULT_TARGET_SPEC = "finger5"
+DEFAULT_TARGET_SPEC = "full14"
 
 
 def get_target_keys(spec=None):