Unique rent payment references

Each rent charge gets a unique remittance reference: SRR plus 7 Crockford characters (no 0/O/I/1), for example SRR7K3MNPQ. Trades use SRJ plus 7.

Pay-by-Bank sends the charge’s SRR to the landlord’s IBAN. The payment_executed webhook marks that row received.

The standing-order helper uses a stable tenancy SRR so the tenant can set it once in their bank. Those lodgements are not auto-marked.

Tenant “I’ve paid” is claimed, not received. Statement CSV/PDF is fallback only (exact cents + unique ref).