* Fix per-provider data loss, division-by-zero, and decode fragility
- Per-provider multi-day queries only merged cost/calls from cache,
dropping categories/models/sessions/tokens. Remove broken cache
shortcut and always do full parse for per-provider periods.
- Remove per-provider daily history double-counting from overlapping
cache + live data.
- Guard maxCost against zero in ActivitySection and ModelsSection to
prevent NaN in bar width calculations.
- Use offset-based ForEach ID in BarTooltipCard to avoid duplicate
model name collisions.
- Make cacheHitPercent, topActivities, topModels, providers use
decodeIfPresent for backward compat with older CLI versions.
- Skip currency switch when FX rate fetch fails with no cache,
preventing rate/symbol desync.
- Use readSessionFile in Gemini parser for 128MB size cap.
- Truncate Codex userMessage to 500 chars like other providers.
* Restore cache-backed trend history for provider-filtered views
The previous commit removed the broken per-provider cache shortcut but
also dropped cache-backed daily history, causing provider-filtered views
to lose trend data outside the selected period range.
Use allCacheDays for historical days (cost/calls per provider is accurate
in cache) and today's entry from the full parse. No overlap since cache
ends at yesterday.
