Extends the salvaged #112860 entry (`workspace`) to the whole class: `plans` and
`home` are bootstrapped alongside `workspace` by `hermes_cli/profiles.py::_PROFILE_DIRS`
and listed as user data in `profile_distribution.py::USER_OWNED_EXCLUDE`, so a
`test_*`/`tmp_*` file inside any of them is a user's file, never scratch.
Trims the contributor's five tests to two invariants: the end-to-end
post_tool_call -> on_session_end path (workspace file survives, a root-level
`tmp_scratch.py` control is still removed) and the empty-dir sweep leaving a
directory under `workspace/` alone. Documents the protected trees in the plugin
README and the built-in-plugins page.
Dropped: test_workspace_project_tree_never_tracked, test_quick_keeps_workspace_test_file,
test_root_level_test_file_still_auto_deleted (folded into the E2E test as its control).
Part of #112859.
0631710ae4