* test: isolate integration test home
Assisted-by: Codex (model: GPT-5, autonomous)
* test: assert integration home isolation
Assisted-by: Codex (model: GPT-5, autonomous)
* test: extend integration home isolation to module-scoped setup
Address Copilot review on #3144.
Add a session-scoped autouse fixture so HOME/USERPROFILE/XDG are redirected
for setup that runs outside a test function (e.g. the module-scoped status_*
fixtures in test_integration_subcommand.py that run `specify init` before any
per-test isolation applies). The function-scoped fixture still overrides HOME
per test.
Also assert Path.home() resolves to the isolated home, since most integrations
(Hermes, catalog) read the home via that API rather than the env vars directly.