Fix callback handling and flag initialization

[ThatOneFBIAgent]

Problem

On Python 3.14, cffi changed how it passes arguments to native callbacks
and how it validates __init__ return values. This caused two distinct errors:

1. TypeError: __init__() should return None, not 'NoneType'
   cffi now intercepts and validates the return of __init__ at a lower
   level, causing it to spuriously reject the standard None return.

2. TypeError: unsupported operand type(s) for &: '_CDataBase' and 'int'
   The status argument now arrives as a raw _CDataBase object instead
   of a plain Python int, breaking bitwise operations in _hasflag.

Both errors surface in _wrap_callback and occur unpredictably during
stream callbacks, including during silence and active playback.

Fix

Bypass CallbackFlags.__init__ entirely in _wrap_callback using
__new__, then set _flags directly via int() cast. This avoids
the cffi __init__ interception and the _CDataBase bitwise issue
in one shot.

Changes

In _wrap_callback, replace:
args = args[:-1] + (CallbackFlags(args[-1]),)
With:
cf = CallbackFlags.new(CallbackFlags)
cf._flags = int(status)

Tested on

• Python 3.14.4, Sounddevice 0.5.5
• Extended idle periods (no audio) no longer trigger the error
• Active playback confirmed working after fix