Function resolve_unified_all 

pub fn resolve_unified_all(
    query: &str,
    root: &Path,
    alias_lookup: &dyn Fn(&str) -> Option<Vec<String>>,
    path_source: Option<&dyn PathSource>,
) -> Vec<UnifiedPath>

Resolve a query to ALL matching unified paths (for ambiguous queries). Returns empty vec if no matches, single-element vec if unambiguous, or multiple elements if query matches multiple files.