Function search_all 

async fn search_all(
    ctx: &ToolContext,
    query: String,
    mode: String,
    source: Option<String>,
    since: Option<String>,
    limit: i64,
) -> Result<Value>

Fan out a search across every enabled workspace (R32–R37): concurrent, per-workspace deadline, per-workspace limit, grouped results, and one errors[] entry per failed/timed-out workspace.