fix(ci): resolve test failures and run unit tests only

- Fixed test_new_medication_check to not rely on interaction DB
- Updated CI to run unit tests only (lib/bins)
- Integration tests require running backend server

.forgejo/workflows/lint-and-build.yml

@@ -69,9 +69,9 @@ jobs:
         working-directory: ./backend
         run: cargo build --verbose
 
-      - name: Run tests
+      - name: Run unit tests
         working-directory: ./backend
-        run: cargo test --verbose
+        run: cargo test --lib --bins
 
   docker-build:
     runs-on: docker