Display PO number (External Document No.) on project details header

[EdiWeeks]

Enhancement

Add the project's Purchase Order (PO) number to the project details header so it's visible at a glance, aligned with the project number / status badges.

The source field in Business Central is the project card's External Document No. (the same field BC uses to record the customer PO against a project).

Where

Project details page → header row that currently reads:

PR00010 [active] [T&M] ⓘ
XYZ – Support & Maintenance
XYZ
📅 Start: 1 Oct 2025 📅 End: 30 Sep 2026

The PO should sit on the same line as PR00010 (or alongside Start/End if it fits better), e.g.:

Code: PR00010 [active] [T&M] ⓘ | PO: 4500123456

Why

PO numbers are needed when invoicing customers — having it on the project page (instead of having to click "Open in Business Central") saves a round-trip for anyone reviewing project status or preparing an invoice.

Notes

• BC source field: External Document No. on the project card. Maps to externalDocumentNo on the BC v2.0 /projects resource.
• The Thyme BC Extension may need to expose this field if it doesn't already — verify against the latest extension before implementing.
• Hide the field entirely when no PO is set on the project (don't show "PO: -" or similar empty state).
• Should also appear in the PDF export (alongside the rest of the header), so customer-facing exports include the PO reference.

Acceptance criteria

• PO number (from BC's External Document No.) renders on the project details header when set.
• Hidden when the field is empty.
• Visible in the Export PDF output alongside the existing header fields.