feat: native C++ reference demo and update-and-run launcher

[ralyodio]

Summary

• Native C++17 ten-screen dashboard over the shared C renderer, with deferred widgets and Linux collectors; no JavaScript runtime or screenshot playback.
• Add cpp/c++ to the latest-main launcher with optimized cached builds, both system and mise commands, and homepage/docs entries. Preserve original hero/logo assets.
• Add a checked mise expansion inventory; further language implementations remain pending the shared-core bindings versus independent-port decision.

Verification

• All 120 unmodified TypeScript screen-body reference frames match exact glyph/color/attribute hashes on Linux.
• CTest covers input, malformed JSON, extreme dimensions, bounded subprocesses, live collector fixtures (GPU, SSH, sessions, HTTP, Docker), PTY tabs/resize/overlays/quit/signals and core conformance.
• Release shared build: 9/9 tests; separate installed consumers: 2/2. Address/undefined sanitizer and optimized LTO builds checked locally.
• Updater regression suite: 7 tests, including cpp cache reuse/revision changes for both managers.
• Existing Bun suite: 167 tests; production web build passes.

Scope

The C++ library API remains experimental. Live collectors are Linux-only; macOS defaults to labelled sample data. Exact body parity is not full interaction/API parity. C-only and additional mise languages are not advertised as implemented. Mise supplies CMake; host GCC/Clang is required.