The agent-instructions row accepted `dshHome`, letting one consumer read a
different harness home than sessions, skills, and storage. Home is process
policy: the plugin now resolves `$DSH_HOME`, else `~/.dsh`, through
`resolveDshHome()` from `@deepseek-ai/dsh-home-paths`, and the config field and
the library's explicit-home option are gone.
Tests and both snapshot fixtures pin the home with `vi.stubEnv('DSH_HOME', ...)`
and the harness's existing `DSH_HOME` export instead of row configuration.
`dsh-skill-filesystem` keeps its own `dshHome`/`agentsHome` fields.
The removed cordis.yml key gets an upgrade guide.