feat(packaging): add an AUR source package linking the system .NET

[ShortArrow]

Adds ivi-cli alongside ivi-cli-bin, following the AUR convention where the unsuffixed name builds from source and -bin unpacks a published binary. The two conflict; a user picks one.

	install size	.NET	runtime fixes
ivi-cli-bin	102 MiB	none needed	wait on an ivi-cli release
ivi-cli	6.5 MB	aspnet-runtime	arrive via pacman

Footprint is not the reason to prefer it, which is worth stating because it is the intuitive reason and it is wrong: starting from a machine with no .NET, aspnet-runtime drags in ~97 MiB of dotnet-runtime + aspnet-runtime + dotnet-host + libunwind (measured), landing the two within a couple of MiB of each other. ivi-cli wins on size only where the runtime is already installed for something else. The reason it earns its place is the last column: a vendored runtime only gets security fixes when we cut a release.

Two accommodations for Arch's SDK

Both were found by the build failing, not by guessing, and both are commented in the PKGBUILD:

• prepare() deletes global.json. It pins 10.0.204 with rollForward=latestFeature, and Arch ships the 10.0.1xx band — latestFeature does not roll down, so the build stopped with "A compatible .NET SDK was not found". The pin serves upstream CI reproducibility; a distribution package builds on the distribution's SDK, and both emit the same net10.0 output.
• -p:AllowMissingPrunePackageData=true. Arch's dotnet-sdk ships without the PrunePackageData folder, and the ASP.NET Core reference otherwise fails with NETSDK1226. The SDK names this exact flag in its own error text.

Also -p:RestoreLockedMode=false (the committed lock files track upstream CI's SDK patch band) and options=('!debug') (no sources to split, so the debug package was an empty /usr/src/debug plus a build-id symlink to nothing — namcap flagged it as an error before the fix).

Verified in a container

makepkg builds from the tag tarball with a matching sha256; .PKGINFO carries depend = aspnet-runtime and nothing else; the payload is /usr/bin/ivicli → /usr/lib/ivi-cli/ivicli plus licences, third-party notices, and bash/zsh completions. Installed and run: ivicli --version → 0.3.1, visa scan completes, doctor reports [OK] dotnet runtime 10.0.11 — the system one this time, not a bundled copy. namcap: four warnings, all expected and documented in packaging/aur/README.md; no errors.

Install guide and the packaging README now describe both packages, including the note that the size intuition is misleading.