In profiling.sampling, exception mode (--mode exception) wrote an empty profile when the thread blocked inside an except block, for example in time.sleep(). The CLI also enabled the collector's skip_idle filter, which keeps only threads that hold the GIL or are on CPU, and a sleeping thread is neither. The unwinder already keeps only threads with an active exception, so exception mode doesn't need that filter.

• Lib/profiling/sampling/cli.py: new _skip_idle_for_mode() replaces the inline expression at the four places that computed skip_idle (run, attach, live run, live attach). It returns False for wall, all and exception mode and True otherwise, so CPU and GIL modes are unchanged.
• Lib/test/test_profiling/test_sampling_profiler/test_cli.py: test_skip_idle_mode_mapping checks the mapping. test_exception_mode_captures_blocked_handler profiles a script that sleeps in an except block and checks that the collapsed output contains the script; it fails without the change (empty output).

Tests:

• PCbuild/amd64/python_d.exe -m test test_profiling.test_sampling_profiler.test_cli (57 tests)
• PCbuild/amd64/python_d.exe -m test test_profiling.test_sampling_profiler.test_modes (15 tests)

• Issue: profiling.sampling: exception mode drops samples from blocked handlers #159865