feat: CPS export support (internal models → vendor format)

[pskillen]

Problem

Once data lives in our internal models (see genericise-import ticket), we have no way to write it back out to a CPS-compatible export.

Intended outcome

Add the ability to export our internal data models to a CSV/export format supported by a given version of a known CPS software (e.g. OpenGD77).

• Generic export layer to allow future CPS brands and versions; OpenGD77 is the first target.
• Round-trip friendly: an OpenGD77 import then export should reproduce an equivalent codeplug.

Scope

• This ticket covers export only. Actual creation/modification of CPS data is handled by the CRUD tickets.

Affected tool(s)

• Shared export code consumed by tools/.

Notes

• Stay static; emit by header name to match the target CPS version's expected columns.
• Depends on the internal data models from the genericise-import ticket.

[pskillen]

The spirit of this ticket has been taken care of by #38 / #39