fix: use Cmd2ArgumentParser so the shell works on cmd2 >=4.0 (#124)

[chryzsh]

AI-assisted contribution — please read before reviewing

This patch was developed with AI assistance (Claude/Anthropic), directed and tested by me. I'm submitting it in good faith that it's correct, not as an expert assertion that it is. Please treat it with whatever scrutiny you'd want for an AI-assisted contribution.

What this fixes

Closes #124. cmd2 ≥4.0 requires every parser factory used with @cmd2.with_argparser to return a Cmd2ArgumentParser (or subclass) — a plain argparse.ArgumentParser now raises a TypeError from cmd2's internal _build_parser. All 17 parser factories in lib/parsers/parsers.py returned a plain argparse.ArgumentParser, so on cmd2 ≥4.0 every single command in the interactive shell is broken, not just get_device — get_user, get_collection, cd, interact, sessionhunter, application, the script commands, the admin commands, all of it.

The fix is: switch all 17 factories to build a cmd2.Cmd2ArgumentParser instead. Also fixed do_decrypt_parsers(), which was missing its return parser entirely — currently dead code (not wired to any command), but a real bug sitting in the same file I was already touching.

Also relaxed the requirements.txt pin. It already had cmd2<4.0.0 (the workaround mentioned in the issue), while pyproject.toml had no upper bound (cmd2>=2.7.0) — so which cmd2 version you got, and whether you hit this bug at all, depended on which of the two files your install path used. Now that the actual incompatibility is fixed, I aligned both to cmd2>=2.7.0 with no upper bound, rather than leaving a workaround pin in place indefinitely for a bug that's now fixed. Happy to leave the pin in place instead if you'd rather be conservative here — this part is more of a judgment call than the rest of the fix.

Reproduction: unpatched main, real cmd2 4.2.2, against a real lab

The dev environment here has cmd2 2.7.0 installed (which doesn't hit the bug), so I built a throwaway venv with real cmd2 4.2.2 to actually reproduce and verify this, rather than just trusting the traceback in the issue.

$ printf 'interact SMS00001\nget_device ps1-pss\nexit\n' | python sccmhunter.py admin -u domainjoin -p '<redacted>' -ip ps1-pss.mayyhem.com -d mayyhem.com -dc dc.mayyhem.com
SCCMHunter v2.0.0 by @unsigned_sh0rt
[!] Enter help for extra shell commands
TypeError: 'interact_parser' must return a 'Cmd2ArgumentParser' (or subclass).
Received: 'ArgumentParser'.

TypeError: 'get_device_parser' must return a 'Cmd2ArgumentParser' (or subclass).
Received: 'ArgumentParser'.

I also checked this wasn't limited to get_device/interact by instantiating the real SHELL class from lib/attacks/admin directly (no network) and running a representative set of commands under cmd2 4.2.2 — every single one failed with the same TypeError:

get_device mc          -> TypeError: 'get_device_parser' must return a 'Cmd2ArgumentParser' ...
get_user someuser       -> TypeError: 'get_user_parser' must return a 'Cmd2ArgumentParser' ...
get_collection SMS00001 -> TypeError: 'get_collection_parser' must return a 'Cmd2ArgumentParser' ...
cd C:\                  -> TypeError: 'cd_parser' must return a 'Cmd2ArgumentParser' ...
interact SMS00001       -> TypeError: 'interact_parser' must return a 'Cmd2ArgumentParser' ...
sessionhunter someuser  -> TypeError: 'do_sessionhunter_parser' must return a 'Cmd2ArgumentParser' ...
cat somefile.ps1        -> TypeError: 'cat_parser' must return a 'Cmd2ArgumentParser' ...

After the fix: same lab, same cmd2 4.2.2 venv

$ printf 'interact SMS00001\nget_device ps1-pss\nexit\n' | python sccmhunter.py admin -u domainjoin -p '<redacted>' -ip ps1-pss.mayyhem.com -d mayyhem.com -dc dc.mayyhem.com
SCCMHunter v2.0.0 by @unsigned_sh0rt
[!] Enter help for extra shell commands
[*] Collecting device...
'value'
[-] Could not find device: ps1-pss

No TypeError — the command reaches the actual AdminService query and fails only on the lookup itself (ps1-pss isn't an exact match in this environment's SMS_R_System, unrelated to this fix). Same result for the representative command set above run against the real SHELL class: all 7 correctly proceed past parsing into their actual request logic (verified they reach real HTTP calls, either succeeding or failing on network/lookup grounds — never on the parser-type check).

Regression / no-breakage checks

• python -m unittest tests/test_parsers.py -v — new test asserting every *_parser/*_parsers factory in PARSERS returns a Cmd2ArgumentParser. Confirmed it fails against the pre-fix code (AssertionError: ... got ArgumentParser) and passes after — this doesn't need cmd2 ≥4.0 installed to catch a future regression.
• python -m py_compile lib/parsers/parsers.py — clean.
• git diff --check — clean.
• Live-tested against a real lab on both cmd2 2.7.0 (this repo's normal venv, still works) and cmd2 4.2.2 (throwaway venv, now works) — no regression on the older version this project currently targets.