fix(deps): adapt to rand 0.10 split Rng/RngExt trait

rand 0.10 moved `random()` and `random_range()` off `Rng` onto a new
`RngExt` extension trait. Two call sites (agent/swarm.rs,
learning/design_search.rs) needed the import updated; no behavioural
change.

cargo build green; cargo test --lib: 1174 passed / 0 failed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: hyperpolymath <6759885+hyperpolymath@users.noreply.github.com>

Author: hyperpolymath

src/rust/agent/swarm.rs

@@ -29,7 +29,7 @@
 use std::sync::Arc;
 
 use rand::rngs::StdRng;
-use rand::{Rng, SeedableRng};
+use rand::{RngExt, SeedableRng};
 use serde::{Deserialize, Serialize};
 use tokio::sync::{mpsc, Mutex};
 use tokio::task::JoinSet;

src/rust/learning/design_search.rs

@@ -31,7 +31,7 @@ use std::collections::BTreeSet;
 use std::fmt::Debug;
 
 use rand::rngs::StdRng;
-use rand::{Rng, SeedableRng};
+use rand::{RngExt, SeedableRng};
 use serde::{Deserialize, Serialize};
 
 /// The minimum surface a domain has to expose for the annealer.