fix(milestones): re-export contract module; fail CI on dead_code

.github/workflows/ci.yml

@@ -28,6 +28,14 @@ jobs:
 
       - run: cargo fmt --check
       - run: cargo clippy --workspace --all-targets --locked -- -D warnings
+
+      # A contract module that isn't re-exported leaves the contract struct,
+      # its generated Client and every helper it calls unreachable, which
+      # surfaces as dead_code warnings on a plain library build.
+      - name: Build without dead_code warnings
+        env:
+          RUSTFLAGS: "-D dead_code"
+        run: cargo build --workspace --locked
       - run: cargo test --workspace --locked
 
       - name: Security audit

contracts/milestones/src/lib.rs

@@ -1170,6 +1170,8 @@ mod contract {
     }
 } // mod contract
 
+pub use contract::*;
+
 /// Pays each contributor their share of `milestone.remaining_budget` (the
 /// unallocated remainder of the pool), computed as
 /// `remaining_budget * contribution.amount / total_budget` — i.e. in