Establish provenance and license for the preserved MRV412 package

[ReidSurmeier]

The screen_config directory contains a byte-preserved MRV412 firmware package. ADR 0001 classifies it as Historical Receiver Firmware and forbids treating it as the installed receiver configuration.

Human provenance work:

• identify the original vendor download or service source
• record acquisition date, package version, supported hardware, and vendor checksums when available
• determine whether public redistribution is permitted
• compare nested archives and image contents in an isolated, non-flashing environment
• retain hashes even if public distribution must later be restricted

Acceptance criteria:

• source and licensing status are documented with primary evidence
• public custody is explicitly permitted or a source-preserving restriction plan is approved
• the package remains excluded from automated installation and flashing paths.