- Reject dates that are not strict YYYY-MM-DD (was accepting full ISO
datetimes, which silently produced empty exports instead of a 400)
and reject from > to with a 400 before touching the team/DB.
- Emit the cashbox_export_download and cashbox_export_subscription_update
audit log events that were declared but never fired, matching the
audit trail every sibling feature already has.
- Restore full type checking on the pdfkit import via `import = require()`
instead of an untyped require() with an eslint-disable.
- Tighten a cashbox.spec.ts assertion to check the exact dialog class
instead of expect.anything(), so it can't pass with the wrong dialog
wired to the Export button.
- Style and announce the export dialogs' error messages using this
codebase's established error-message/role=alert pattern.
