Add bld self-update to reinstall the CLI

[Antaris]

update still updates the Build submodule. This adds a first-class command that does what a fresh ./scripts/install.sh does: republish and replace the installed bld binary.

Usage

bld self-update                 # clone main and reinstall
bld self-update --ref v0.2.0    # install a branch or tag
bld self-update --source .      # publish a local BuildCLI checkout
bld upgrade                     # alias

The install location matches the existing scripts (~/.local/share/ingenium/bld on Unix, %LOCALAPPDATA%\Ingenium\bld on Windows), including BLD_INSTALL_DIR / BUILDCLI_INSTALL_DIR and --install-dir.

Notes

• self-update and upgrade are registered as known commands so they are not forwarded to Cake.
• Publish is self-contained single-file by default, same as scripts/install.sh.
• Unit tests cover routing, publish arguments, and the install service with fake git/dotnet. They do not clone or publish for real.

  

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