v5.3.12

Added the GCC toolchain to the Windows bootstrap via Scoop in bootstrap.ps1, installed in Phase 3 (Language Servers) alongside llvm and clangd to give C and C++ development a native GCC option, with a package description added to Get-PackageDescription. update-all now passes --include-unknown to the winget upgrade command, so packages update even when winget does not recognize the source, which covers manually installed applications.

Removed the -SkipUpdate / --skip-update parameter and the Phase 7 (Update All) step from both bootstrap.ps1 and bootstrap.sh, because bootstrap should install and the update pass added a lot of time without always being necessary. Users run up (update-all) separately when they want updates. The README Bootstrap Options table dropped its "Skip update" row.