Function resolve_qualified_object 

fn resolve_qualified_object(
    object_text: &str,
    alias_map: &BTreeMap<String, String>,
    default_db: &str,
    default_schema: &str,
) -> Option<ObjectId>

Resolve a dot-qualified object prefix to an ObjectId.

• 1 part: alias map lookup (case-insensitive), then fallback to default_db.default_schema.name
• 2 parts: default_db.part0.part1
• 3 parts: part0.part1.part2
• 4+ parts: None