`_ANTIGRAVITY_WORKFLOW` is shared by the global and project-scoped installs,
which write SKILL.md to different locations (~/.gemini/config/skills vs
.agents/skills). The template named the global path unconditionally, so
`install --project --platform antigravity` (and `antigravity install
--project`) emitted a workflow pointing at a file that scope never writes -
a dangling reference on any machine without a prior global install.
Refer to the skill by name rather than by location, matching what every
block in always_on/ already does. Antigravity resolves it from the
`name: graphify` frontmatter in either scope, so no path interpolation is
needed and neither scope can dangle.
The existing tests only asserted the workflow file exists, which is why this
shipped; add coverage that the generated workflow names no skill path, in
both project and global scope.