FOLLOW-UP (Leha: not a bug, follow-up).
get_macro_series / get_latest_macro defaulted region='rf', but CBR mortgage_*
series live under 'sverdl' in macro_indicator (key_rate under 'rf'). Only caller
passes region explicitly so no active leak, but a future caller omitting region
would silently get None — latent footgun. region now str|None; when None →
_canonical_region (mortgage set sourced from _CBR_SERIES_MAP, single source of
truth). Explicit region always wins → existing callers unchanged. Region-binding
tests added. 159 tests pass.
Documented (NOT code-fixed — upstream data-quality): mortgage_debt /
mortgage_overdue stay empty in macro_indicator because cbr_mortgage_series.period
holds value-like garbage (e.g. '10054588.0') for the Debt series — corruption
from the upstream CBR-XLSX scraper that built domrf.db (imported verbatim by
44_import_anton_db.py), NOT an ingest bug. 123_macro_indicator.sql correctly
skips unparseable periods. Needs a separate scraper re-ingest (idempotent
backfill once period is valid). Refs #945
