Function compute_embeddings 

pub fn compute_embeddings(
    graph: &KnowledgeGraph,
    dim: usize,
    walks_per_node: usize,
    walk_length: usize,
) -> HashMap<String, Vec<f64>>

Compute node embeddings using random walks + Skip-gram.

• dim: embedding dimension (default 64)
• walks_per_node: random walks starting from each node (default 10)
• walk_length: length of each walk (default 40)

Returns a map of node_id → embedding vector.