Introduce ability to add invoice notes on the invoice PDF

🔍Problem Statement

Currently, Pelcro invoices do not support adding invoice notes directly on the invoice. This limits flexibility for businesses that need to include contextual details (e.g., billing references, legal notes, or custom instructions).

👤 User Story

As a business owner,

I want the ability to add and update invoice notes directly within the invoice view,

So that I can provide additional context or instructions that are clearly displayed on the invoice and carried over to the PDF version.

🎯 Definition of Done (DoD)

Introduce ability to add invoice notes on the invoice view similar to setting the PO value in the invoice view.
The invoice notes should appear in the PDF.
You can update the invoice notes after creating it similar to PO.
Invoice notes are saved to the invoice record and retrievable via the Core API.

Test cases:

General Invoice Notes (Core Cases)

C5876: Verify adding a note on an invoice saves successfully.
C5877: Verify the note persists after refresh/reopen.
C5878: Verify updating a note overwrites the old content.
C5879: Verify clearing a note removes it from the invoice.
C5880: Verify the note appears on the PDF after saving.
C5881: Verify updated/cleared notes refresh on the next PDF download.
C5882: Verify the Default UI download includes the note.
C5883: Verify Core API (GET /invoices/{id}) returns the note field.
C5884: Verify creating/updating a note via Core API reflects in Platform & PDF.
C5885: Verify multiline, special characters, and long notes render correctly in UI & PDF.
C5886: Verify invoice state rules (draft/open/paid) are respected when editing notes.

Advance Invoice (Manual Renewal Action)

C5887: Verify advance invoice supports adding a note and saving it.
C5888: Verify note appears on the PDF and updates on re-download.
C5889: Verify note is returned via Core API.
C5890: Verify adding/updating via API reflects in Platform & PDF.
C5891: Verify note is visible when opening invoice from the renewal timeline entry.

Automatic Renewal Invoice (System-Generated)

C5892: Verify adding/updating/clearing a note works on auto-generated invoices.
C5893: Verify note appears on PDF and updates correctly.
C5894: Verify Core API returns the note value.
C5895: Verify adding note after auto-generation still syncs to PDF/API.

Standalone Invoice

C5896: Verify adding/updating/clearing notes works like other invoice types.
C5897: Verify note appears on PDF and updates correctly.
C5898: Verify note is retrievable via Core API.
C5899: Verify long/multiline/special notes render correctly without layout issues.

Invoice from eCommerce Order

C5900: Verify adding/updating/clearing a note on eCommerce invoice works and persists.
C5901: Verify note appears on PDF and reflects updates.
C5902: Verify Core API (GET /invoices/{id}) returns the note.
C5903: Verify note remains intact through eCommerce flows (refunds, partial refunds).
C5904: Verify Default UI download includes the note.

Pelcro