gt2gh

Command identity and discovery

Keep gt2gh as the project, repository, skill, release-asset, and Homebrew formula name. Homebrew installs the executable as g2g; source builds and unrenamed release archives use gt2gh.
At the start of a task, reuse a usable command already resolved in the task context. Otherwise, discover it once locally: try g2g --version first, then gt2gh --version. Select the first command that succeeds. If neither works, state that the user must install brew install shhac/tap/gt2gh or provide a source/release-archive gt2gh binary; do not assume either command exists.
Record the selected command as the task's GT2GH_CMD and use it for every later invocation. Do not re-detect it unless it fails or the environment changes. Use g2g in Homebrew examples and gt2gh in source/archive examples.