* fix: exclude ECC skills from antigravity install target
* test(install): cover antigravity skills exclusion
Two tests encoded the collision the parent commit fixes.
install-manifests used skills/example as its example of a supported
antigravity path; it now asserts skills are filtered and uses
commands/example for the positive case, so the test still proves
supported paths survive filtering.
install-apply asserted .agent/skills/tdd-workflow/SKILL.md exists. That
directory is antigravity's agent directory and already receives ECC
agents/, so the assertion was pinning ECC skills and ECC agents to the
same destination. Inverted, with the reason recorded inline.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---------
Co-authored-by: Calum Reeves <reevesc88@users.noreply.github.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
