v0.3.23

Fixed

• Usage heatmap stale daily rows — the Usage tab heatmap could show 0
  work hours for days with 10+ hours of active coding. Two root causes fixed:
  1. Stale today row (src/index.ts): the daily downsample job computed
     today's row at startup or UTC midnight with whatever samples existed at
     that moment, then never refreshed it. On machines that are not on 24/7,
     the UTC-midnight timer frequently does not fire, leaving today's row
     frozen at startup values. Fix: a new refreshTodayDaily() timer now
     calls downsampleDay directly every 10 minutes, keeping today's row
     current throughout the session. Additionally, runDailyDownsample
     now force-recomputes all within-retention days at startup and midnight,
     healing stale rows left over from previous runs (e.g. Monday's row at
     Tuesday's startup). Beyond-retention days are left untouched (raw
     samples may be pruned, so recompute would destroy good rows).
  2. Active-minutes undercount (src/usage-history/daily.ts): the
     computeDailyRow algorithm skipped any 60-second interval where the
     activityKey (tokens_in, tokens_out, tokens_cached,
     concurrent_sessions) was identical between two consecutive samples.
     For bursty coding traffic, many 60-second windows had no new token
     movement, so session-open intervals (reading, thinking, waiting on a
     generation) were not counted. Fix: the skip is now gated on
     concurrent_sessions === 0 in both samples — if a session is open,
     the interval counts as active even without token movement.