* feat(dashboard): request count log per provider, per date (#4009)
Some providers bill by request rather than by token, so operators need
a plain per-provider, per-date request count breakdown, not just token
aggregates. Adds a new getProviderDailyUsageRows() aggregation query
(src/lib/db/usageAnalytics.ts), a dedicated GET
/api/usage/requests-by-provider-date route (kept separate from the
frozen /api/usage/analytics route to respect the file-size baseline),
and a sortable, single-date-filterable table on Dashboard -> Analytics.
Closes#4009
* chore(6812): re-sync onto release tip; CHANGELOG → changelog.d fragment (fragments-first)
28fcd418a4