Stage production icons for desktop builds and publish (#168)

* Stage production icons for desktop builds and publish

- add shared brand asset paths and a Windows .ico asset
- stage Linux/Windows icons in desktop artifact builds
- override and restore publish favicon during server CLI publish

* 'blip'

* Fix PR review issues for publish icon staging

* Refactor brand assets and harden Windows desktop build setup

* Apply remaining server orchestration updates

* Fix production mac icon asset

Co-authored-by: Theo Browne <t3dotgg@users.noreply.github.com>

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Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Theo Browne <t3dotgg@users.noreply.github.com>