Add HDFC PDF statement import support

[codeforester]

Context

HDFC spreadsheet imports are available for years where the bank provides old Excel .xls statements. Older years may only be available as PDF statements.

Desired behavior

• Parse text-selectable HDFC PDF statements when spreadsheet exports are unavailable.
• Infer the HDFC account number suffix/full statement account where available.
• Extract statement period, transaction date, value date if present, narration, reference, debit/credit amount, and closing balance.
• Reuse the same account auto-routing, row-balance sanity checks, latest balance snapshot, import history, and processed-file naming model used by HDFC .xls imports.
• Keep password-protected or OCR-only PDFs as explicit follow-up work if samples require it.

Notes

This is future work; .xls remains the preferred HDFC import path when available.