When a user switched profiles and created a new session, the session
was saved to the default profile directory instead of the active
profile directory — because get_hermes_home_for_profile() silently
fell back to _DEFAULT_HERMES_HOME when the profile directory didn't
exist yet on disk.
Root cause: api/profiles.py:156 had `if profile_dir.is_dir(): return
profile_dir; return _DEFAULT_HERMES_HOME`. New profiles (no session
yet, so no dir) routed every session back to default.
Fix: remove the is_dir() guard, return the profile path
unconditionally. The profile directory is created on first use by
the agent/session layer.
5 regression tests in tests/test_issue1195_session_profile_routing.py:
existing-profile, non-existent-profile (the core fix), None, empty-
string, 'default' all return the expected path.
Co-authored-by: bergeouss <bergeouss@users.noreply.github.com>