v1.4.0

Track what you actually paid alongside what the usage was worth. Settings → Spend is a manual USD ledger (platform + date + amount + note) with add/edit/delete, and the dashboard gains a Spend vs Value card (total spent vs usage Value with a value/spend ratio).

Added

• Settings → Spend ledger. Manual USD entries per platform and date with add/edit/delete/clear-all, a month-by-month spend table, and a total / last-12-months / entries summary. Entries persist in chrome.storage.local (spendEntries), are normalized and validated on read, and ride along in the settings backup export/import.
• Spend vs Value card. Dashboard KPI showing total spent (date-filtered) against usage Value, with a Nx value-per-dollar ratio (- when nothing is spent).
• Pure ledger helpers in shared/spend.js (normalize/validate/aggregate/ROI, no chrome/DOM) covered by tools/tests/spend.test.mjs.

Changed

• Removed the Avg Cache Hit Rate KPI card. Per-model hit rates still live in chart 5 (Cache Hit Rate by Model) and the workspace/model tables; only the summary card is gone. Its maxHitRate/minHitRate aggregate fields are removed with it.
• The Spend date picker reuses the filter bar's shared calendar grid instead of its own copy.