fix: the pin is not a floor, and stop demanding CMake and cpanm

[ralyodio]

--system was unusable on any machine that was not already pinned, which is every stock Mac. Reported as "I have to use --mise perl always".

Three separate causes.

The pin was treated as a floor

The version gate in #50 compared the resolved tool against the mise pin. So system Perl 5.40 was refused against a 5.44 pin, and Ruby 3.3 against 4.0.6, even though both build these bindings perfectly well. That is a regression from #50 and it defeated the point of the flag.

The gate now fails only below the version the port itself declares it needs, and merely mentions anything between that floor and the pin:

hqtui-demo: Building with your perl 5.40.1; this revision pins perl 5.44.0.0.
            Rerun with --mise if the build fails.

Floors come from each port's own manifest: ports/go/go.mod (1.22), Cargo.toml rust-version (1.75), requires-python (3.10), hqtui.gemspec (3.1), composer.json (8.1), Makefile.PL MIN_PERL_VERSION (5.20), cmake_minimum_required (3.20). Bun keeps a real floor of 1.4.0, since 1.3 genuinely cannot parse a lockfileVersion: 2 bun.lock — the bug #50 was opened for, still caught:

hqtui-demo: …/bun/1.3.14/bin/bun is 1.3.14, and this demo needs bun 1.4.0 or newer.

CMake was mandatory

CMake is a build tool for the native binding, not the language runtime --system is about, and the C++ compiler still comes from the host. When the host has no CMake and mise is installed, the pinned one is now borrowed with a note instead of refusing to run. With no mise, the message names the actual command for that platform (brew install cmake on Darwin).

macOS ships Perl but no cpanm

--system perl died at cpanm: not found before building anything. The standalone installer is now fetched into the private demo cache, the same place FFI::Platypus already went. Nothing global is touched, and the failure message no longer asks for a manual step.

Verified

On a box whose system Perl (5.40.1) and Ruby (3.3.8) are both below the pins, with no CMake and no cpanm on PATH:

• --system perl borrows the pinned CMake, fetches cpanm, builds FFI::Platypus and the native binding, and renders the dashboard.
• --system ruby renders the dashboard.
• --system typescript with Bun 1.3.14 still fails, with the message naming both versions.

15/15 updater tests, sh -n, dash -n, and shellcheck -s sh (only the pre-existing SC2016 at the perl -MConfig line).

test_declared_floors_match_the_ports_own_manifests reads the floors back out of demo.sh and compares each against the manifest that states it, so a port raising its requirement cannot leave the launcher starting a build that cannot succeed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01TbGYCRHZsZUsQwRCLafhMF