Fix AudioRecorder leak and SEL5_MACRO_RANGE misparse in Logic

[MarkRose]

• Logic::recordStart leaked the AudioRecorder when initialize() failed
  (e.g. file could not be opened due to a bad path or permissions).
  On the failure path it called recordStop(), which removes the
  recorder from rx_splitter, but the recorder was never registered as
  a splitter sink at that point (addSink() runs later, only on
  success), so the removal was a no-op and the sole pointer to the
  object was dropped. Now the recorder is deleted directly on the
  failure path instead of relying on recordStop().

• Logic::initialize mishandled a SEL5_MACRO_RANGE config value that is
  missing the required comma separator. string::find(",") returns
  npos, which was cast to int and used as a substr() length/position,
  silently producing sel5_from == sel5_to == the entire (malformed)
  string instead of reporting the bad config. Now the missing-comma
  case is detected explicitly and an error is logged instead of
  silently deriving a degenerate range.

Co-Authored-By: Claude Opus 4.8 [email protected]