* fix(dashboard): count live usage_history rows in Free Tier 'used this month' (#10381)
* fix(dashboard): use an indexable UTC month-range predicate for used-this-month (#10381)
sumUsageTokensThisMonth() filtered usage_history with
substr(timestamp, 1, 7) = strftime('%Y-%m', 'now') — a substr() expression
SQLite cannot use a range index on, and fragile against any timestamp
that isn't exactly ISO-shaped. Replace with an indexable inclusive-start/
exclusive-end UTC range: timestamp >= <month start> AND timestamp <
<next month start>, matching the ISO 8601 format saveRequestUsage()
already writes.
Adds a boundary regression test: the first instant of the current month
is included, the last instant of the previous month is excluded, and a
next-month row is excluded too (covers the upper bound substr() could
never express).
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Co-authored-by: adevwithpurpose <adevwithpurpose@users.noreply.github.com>
