NetExperts Support and Advanced Support 1.5.4.2, Flutter build 73

Open Door product icons, normal-width access wording, selected upstream security
fixes, and FFmpeg 7.1.5 for Windows/Linux with the existing custom patches.
Mac builds do not link FFmpeg. Runtime and installer version is 1.5.4.2; Cargo's
SemVer package version is 1.5.4 and Flutter uses 1.5.4+73.

Each installation defaults staff login to Yes. Only an explicit No during that
installation disables it. A later Settings choice persists until reinstall.
Local recipient approval, displayed-password access and authenticated relay
fallback remain available. RustDesk upstream licence/copyright notices and
internal compatibility identifiers are retained.

The existing automatic updater compares only the first three version components.
Users already on 1.5.4.1 must install this revision from the website or AUR.
The crypto-bigint timing advisory RUSTSEC-2026-0387 remains deferred pending a
compatible upstream fix; this release does not claim to fix that advisory.

Use: python3 prepare.py PROFILE /new/empty/destination
Profiles: windows, macos, linux-advanced, linux-support.
Each reconstructed source tree is checked against its complete SHA-256 manifest.
Build records, platform instructions, generated variants, dependency locks and
vendored source are included. Retained toolchains/caches were used. This is not
a clean-room or bit-for-bit reproducibility claim. Original 1.4.8 and previous
release environments remain preserved separately.
