ci: run Soroban contract tests in CI as a quality gate

.github/workflows/ci.yml

@@ -169,7 +169,7 @@ jobs:
           retention-days: 14
 
   contracts:
-    name: Contracts Build
+    name: Contracts Build & Test
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -189,6 +189,12 @@ jobs:
       - name: Build
         working-directory: ./contracts
         run: cargo build
+      - name: Test
+        working-directory: ./contracts
+        env:
+          RUST_BACKTRACE: 1
+          CARGO_TERM_COLOR: always
+        run: cargo test -- --nocapture
       - name: Test (unit + property/fuzz)
         working-directory: ./contracts
         # Property tests use a fixed, bounded case count (see

docs/governance/CONTRIBUTING.md

@@ -43,6 +43,20 @@ at first.
 > [CI/CD Pipeline Guide](docs/CICD_GUIDE.md) before making any changes related to secrets, sensitive
 > data, or smart contracts.
 
+### Local Verification
+
+> [!IMPORTANT] Before opening a pull request, verify all contract checks pass locally. These are the
+> exact commands the CI pipeline runs.
+
+```bash
+cd contracts
+cargo fmt --check
+cargo clippy
+cargo build
+cargo test
+```
+
+Any failure here will also fail the pull-request workflow, so fix issues before submitting.
 Adding or editing a course lesson? See
 [docs/backend/CURRICULUM_AUTHORING.md](../backend/CURRICULUM_AUTHORING.md)
 for the required fields and the `npm run validate:curriculum` command CI