v1.0.1: demat equity symbol resolution

1.0.1

New

• Demat equity holdings now carry symbol + exchange. NSDL/CDSL
  statements identify an equity by ISIN only, so Equity rows used to lack an
  exchange trading ticker. The NSE symbol + exchange are now backfilled from the
  ISIN database after parsing (parsers._isin.batch_equity_symbols,
  _enrich_demat_equities), mirroring the existing MF amfi / type
  enrichment — so a demat holding identified only by ISIN can be priced via a
  symbol-keyed feed. Unresolvable ISINs stay None. Requires
  casparser-isin>=2026.6.9 (ships the symbol columns + ISINDb.batch_isin_lookup).