GGUF source tests fail in sandboxed builds (Nix, Docker) #306

Bug

Two tests added in v0.8.6 fail in any sandboxed build environment (Nix, Docker without network, CI with restricted egress):

• models::tests::test_catalog_has_significant_gguf_coverage
• models::tests::test_catalog_popular_models_have_gguf_sources

Error

thread 'models::tests::test_catalog_has_significant_gguf_coverage' panicked at llmfit-core/src/models.rs:1450:9:
GGUF source coverage is only 0.0% (0/1107), expected at least 25%

thread 'models::tests::test_catalog_popular_models_have_gguf_sources' panicked at llmfit-core/src/models.rs:1405:13:
Model meta-llama/Llama-3.3-70B-Instruct should have gguf_sources but has none

Root Cause

These tests expect the GGUF source catalog to be populated from HuggingFace at build time. In sandboxed environments (Nix builds, network-restricted Docker, offline CI), no network access is available, so the catalog is empty and the assertions fail.

Impact

• nix build / nix profile install github:AlexsJones/llmfit fails on v0.8.6
• Any CI pipeline that runs tests without network access will fail
• v0.8.5 builds fine (tests didn't exist yet)

Suggested Fix

Gate these tests behind a feature flag or #[ignore] attribute so they don't run in sandboxed builds:

#[test]
#[ignore] // Requires network access to populate GGUF sources
fn test_catalog_has_significant_gguf_coverage() {

Or check for network availability at the start of the test and skip gracefully.

Workaround

In flake.nix, add checkFlags to skip the two tests:

checkFlags = [
  "--skip" "models::tests::test_catalog_has_significant_gguf_coverage"
  "--skip" "models::tests::test_catalog_popular_models_have_gguf_sources"
];

Environment

• NixOS/nixpkgs unstable
• llmfit v0.8.6
• nix build with default sandbox enabled