When state.db has many non-cron sessions, the normal sidebar query caps
at CLI_VISIBLE_SESSION_LIMIT (20) rows ordered by latest activity. Older
cron runs get squeezed out before _include_project_hidden_background_sidebar_sessions
can rescue them, making them invisible under their project chip.
Add a second-pass cron-only query with a higher cap (CRON_PROJECT_CHIP_LIMIT=200)
that merges into the CLI session list. The project-chip rescue layer then
marks them default_hidden so they stay addressable without polluting the
default sidebar window.
Verification: regression test seeds 25+ newer non-cron sessions and asserts
the older messageful cron session still appears with project_id set.
