The new CLI/gateway insights pass counted ALL state.db sessions, but
WebUI-native sessions are persisted to state.db with source='webui' AND
already counted from the sidecar _index.json first pass — double-counting
them in totals, model breakdown, and daily charts. Add
`AND COALESCE(source, '') != 'webui'` so only CLI/gateway/cron/tui rows are
added by the second pass.
Adds regression tests proving (a) CLI + Telegram sessions appear in totals
and (b) a webui-source state.db row is not double-counted against its
_index.json entry.
Co-authored-by: wind-chant <wind-chant@users.noreply.github.com>
