Cross-platform test tooling + WSL1/WSL2 + Ubuntu 22.04 support

[darkn3rd]

Summary

Adds a cross-platform verification and test-harness toolchain for
script-tut's lessons, and extends platform support to WSL1, WSL2, and
native Ubuntu 22.04, alongside a round of correctness fixes surfaced by
testing across all of them.

New tooling (scriptbox/scripts/)

• verify_commands.rb - reports every lesson language's resolved
  binary, package identity, and version across MSYS2/Cygwin/WSL1/WSL2/
  native Windows/macOS, with table/json/yaml/csv output.
• run_all_tests.rb / run_all_tests.ps1 - drives rake/psake
  across every lesson directory and prints a unified pass/fail/skip
  summary, with table/json/yaml/csv/junit output and
  {a,b,c}-style area/language selectors.
• compile_check.rb - builds every compiled-language lesson
  (C++/C#/Go/Java/Rust) in parallel and reports success/failure per
  language.
• A --skip-compile flag / TESTBOX_SKIP_COMPILE env var lets
  run_all_tests reuse a build compile_check.rb already did instead
  of rebuilding sequentially.

Platform support

• New Wsl2ShellScript (testbox/Script.rb) - WSL2 now gets the same
  wslpath-based Windows-binary invocation WSL1 already had, for
  win_scripts (Batch/JScript/VBScript) lessons.
• windows_host_shell's process-ancestry walk now sees past any
  intermediary process, not just a transient cmd.exe /c wrapper -
  fixes run_all_tests.rb always selecting the wrong shell class
  (and the long-standing PowerShell-lesson hang that turned out to be
  a symptom of it).
• TestBox.psm1's cmd/cscript resolution now works under WSL
  interop, not just native Windows (PATHEXT-based bare-name resolution
  is Windows-only; WSL needs the .exe extension explicit).
• Added scriptbox/config/ubuntu2204.yml and
  scriptbox/config/wsl1_ubuntu2604.yml for unattended provisioning.

Bug fixes

• ensure_compiled!/Confirm-TestBoxCompiled now run make clean
  first and correctly select Makefile.win on native Windows
  (matching compile_check.rb, which already did) - fixes stale
  cross-environment build artifacts breaking links.
• All 5 lessons/compiled_lang/*/Makefiles: clean:'s mkdir -p
  created a literal -p directory under a cmd.exe recipe shell (no
  -p support there) - fixed to the portable -@mkdir idiom already
  used elsewhere in the same files. That stray directory was also
  silently corrupting -?/-h argument parsing on MinGW-built C++
  binaries via argv glob-expansion.
• Version-parsing fixes across gawk, g++, mksh, groovy, dash, ksh93;
  Debian/dpkg packaging noise (+git..., ~beta.N, -revision)
  stripped from displayed versions.
• find_on_path now tries PATHEXT extensions when searching an
  explicit directory list (fixes false "MISSING" for Batch's
  date/grep dependents under WSL).
• Native Windows no longer misidentifies C:\Windows\System32\bash.exe
  (WSL's own launcher stub) as a real bash.

Lessons

• Added lessons/compiled_lang/cpp/src/d10.input.cpp (C++ had no D1
  "Reading a Single Character" implementation at all).
• Various lesson cleanup/reorganization across posix, bash,
  wsh.vbscript, win_scripts (scratch/deceased pruning, a few new
  variants).

Test plan

• verify_commands.rb and run_all_tests.rb/.ps1 run clean on
  native Windows (PowerShell/cmd), WSL1, and WSL2
• compile_check.rb parallel build verified on native Windows and
  WSL2
• All 5 compiled-language lesson suites pass with zero skips
  (C++ included, after adding D1)
• --skip-compile verified to skip rebuild on both rake and
  psake paths

[darkn3rd]

LGTM

[darkn3rd]

LGTM