Function code_entity_id 

pub fn code_entity_id(
    kind: &CodeEntityKind,
    qualified_path: &str,
    scope: &ScopeKey,
) -> EntityId

Build a canonical EntityId for a code entity with scope context.

Format: code:{scope_prefix}:{kind}:{qualified_path}

The scope prefix uses repo_id if available, then falls back to workspace_id, then to namespace. This ensures the same qualified path in different repos/workspaces produces different IDs.

This is deterministic — the same inputs always produce the same ID.