Adds EL_TRUE/EL_FALSE convenience macros to el_runtime.h alongside the
existing EL_NULL, making boolean-returning builtins readable without
raw (el_val_t) casts. Documents all value macros in the header comment.
Also lands el_arena_push/el_arena_pop — a scoped string arena for CLI
programs that never call el_request_start/end. The compiler can push a
mark before a compilation unit and pop it after to free intermediate
strings, reducing peak RSS during long compile runs.
- lang/tools/install/el-install.el: El program that fetches the latest
release from the Gitea API, downloads el-sdk-latest.tar.gz, and
extracts it into ~/.el (or a custom prefix passed as argv[1])
- lang/tools/install/manifest.el: build manifest for the el-install package
- .gitea/workflows/sdk-release.yaml: build elb, epm, and el-install
binaries; bundle elc + elb + epm + runtime files into el-sdk-latest.tar.gz;
attach both the tarball and el-install binary to the Gitea release
alongside the existing per-file GCP uploads
Will Anderson