Users can now set sessionDir in global or project settings.json instead
of passing --session-dir on every invocation. CLI flag takes precedence,
then settings.json, then extension hooks.
Closes#2429
Co-authored-by: Sam Collins <81678+smcllns@users.noreply.github.com>
Co-authored-by: Mario Zechner <badlogicgames@gmail.com>
Google's promptTokenCount includes cachedContentTokenCount, so using it
directly as the input token count causes double-counting when calculateCost
multiplies input by the input rate AND cacheRead by the cacheRead rate.
The google-gemini-cli provider already handles this correctly (subtracting
cachedContentTokenCount from promptTokenCount), but google.ts and
google-vertex.ts were using the raw promptTokenCount.
This fix aligns both providers with the google-gemini-cli behavior.