The manager dashboard "Approved This Month" card only counted POs whose
current status is MGR_APPROVED, so approvals that had already moved on to
payment, delivery, or closure dropped out of the count. Managers could not
see what happened to the POs they approved this month.
- Count every PO whose `approvedAt` falls in the current month across all
post-approval statuses (MGR_APPROVED → ... → CLOSED). `approvedAt` is set
once at approval and persists, so it is the correct anchor.
- Introduce a shared `POST_APPROVAL_STATUSES` constant (includes the
previously-omitted PARTIALLY_CLOSED). This also fixes Total Approved Spend
and the vessel/monthly breakdowns, which were silently dropping
partially-received POs.
- Make the card a link into /history with an approval-date filter applied
(?approvedFrom=<startOfMonth>) so a click shows the full set with each PO's
current status, as requested.
- Add `approvedFrom`/`approvedTo` filtering to the history page, its filter
UI, and the reports export route so the deep-link and exports stay in sync.
Scope note: the count remains org-wide, consistent with every other card on
the manager dashboard.
Adds an integration test covering the moved-on case and the date window.
Fixes#32
