The prompts used to arrive at this change since the previous commit
User reported the Dynamisch kwartaal Roundcube filter is empty and asked for a new file containing a dynamic invoice-quarter filter while keeping the rest of the plan approved.
Any special observations that may be relevant for version management for this version. Be brief.
invoice_dynamic_quarter.sieve uses Date header year capture plus regex month tests and compiles with sievec. Existing untracked financ.sieve, codex.session, roundcube.txt, plan.md, and verplaats_log.json were left untouched.
