Filter crashes curitz on invalid regex subpattern match with eg. ( and ) characters

[runborg]

if trying to search for a string including a not regex valid set of ( and ) characters makes curitz exit with a traceback:

--> $ curitz
Traceback (most recent call last):
  File "/home/runarb/.local/bin/curitz", line 8, in <module>
    sys.exit(main())
  File "/home/runarb/.local/pipx/venvs/curitz/lib/python3.10/site-packages/curitz/cli.py", line 1182, in main
    curses.wrapper(uiloop, config)
  File "/usr/lib/python3.10/curses/__init__.py", line 94, in wrapper
    return func(stdscr, *args, **kwds)
  File "/home/runarb/.local/pipx/venvs/curitz/lib/python3.10/site-packages/curitz/cli.py", line 404, in uiloop
    runner(screen, config)
  File "/home/runarb/.local/pipx/venvs/curitz/lib/python3.10/site-packages/curitz/cli.py", line 865, in runner
    create_case_list(config)
  File "/home/runarb/.local/pipx/venvs/curitz/lib/python3.10/site-packages/curitz/cli.py", line 454, in create_case_list
    sorted_cases = sortCases(cases, field="updated", filter=casefilter)
  File "/home/runarb/.local/pipx/venvs/curitz/lib/python3.10/site-packages/curitz/cli.py", line 420, in sortCases
    if re.match(
  File "/usr/lib/python3.10/re.py", line 190, in match
    return _compile(pattern, flags).match(string)
  File "/usr/lib/python3.10/re.py", line 303, in _compile
    p = sre_compile.compile(pattern, flags)
  File "/usr/lib/python3.10/sre_compile.py", line 788, in compile
    p = sre_parse.parse(p, flags)
  File "/usr/lib/python3.10/sre_parse.py", line 955, in parse
    p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
  File "/usr/lib/python3.10/sre_parse.py", line 444, in _parse_sub
    itemsappend(_parse(source, state, verbose, nested + 1,
  File "/usr/lib/python3.10/sre_parse.py", line 843, in _parse
    raise source.error("missing ), unterminated subpattern",
re.error: missing ), unterminated subpattern at position 5

This happens because the string entered is passed right into a regex without error handling,
Entering a incomplete subpattern should generate a better error message to the user.