add tax-report filters and yearly document check

[OrellBuehler]

Summary

• custom_field_query on list_documents — pass-through JSON expression filter (e.g. ["Betrag", "gt", 100] or nested ["AND", [...]]) so agents can filter by amount/tax-year custom fields and sum deductions in one call
• inclusive date filters: created__date__gte/lte and added__date__gte/lte alongside the existing exclusive gt/lt, with descriptions marking which is which
• yearly_document_check helper — compares a year against the previous year per correspondent + document type (optionally scoped by tags__id__all) and reports missing_this_year (with example titles from last year), new_this_year, and totals
• __in filters: correspondent__id__in and document_type__id__in (comma-joined by buildQS)
• README tool catalog and filter notes updated

Test plan

• three new tests: filter pass-through assertions, a full missing-combo scenario, and tag scoping
• all 140 tests pass; format/lint/typecheck green (prek hooks ran the same gates on commit)

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