[theKBro (theKBro)]

Changes import processing in Rust and .NET to retain package failures through the complete import run, continue attempting later packages, and return exit code 1 if any non-ignored package fails. A later success, ignored unavailable package, or no-op cannot clear an earlier failure.

Fixes .NET's unavailable-package classification to recognize the core repository's actual no package matched the supplied query message as well as the existing spelling. Recognized package-not-found and no-applicable-installer errors remain ignorable with --ignore-unavailable; installer exit failures, hash verification errors, and arbitrary exceptions are not ignored.

Preserves successful package-level dry-run behavior, including Rust search errors and missing packages, without invoking installers. Dry-run does not mask file parsing or repository initialization errors. No-op results and --no-upgrade skips remain successful. .NET installed-state lookup errors are now handled per package, so they cannot stop later packages from being processed.

Adds handler-level regression coverage in both implementations for mixed failure/success imports, thrown installer errors, --ignore-unavailable, dry-run, and no-op behavior. Additional cases cover .NET installed-state lookup failures and Rust discovery errors. Updates the README's import behavior and compatibility limits.