Community-supported CMake build

[leha-bot]

Is your feature request related to a problem? Please describe.
This is a pure C++ infrastructure request

Describe the solution you'd like
I would like to request the CMake support for build as an additional community-driven build option.

[clholgat]

CMake / non-Bazel build support isn't available in the current release and isn't something we're actively working on — we've documented this as a known gap in Choosing Valdi. Bazel is currently required.

A community-supported CMake build would be a great contribution if anyone wants to take it on.