ci: run 'cargo shear'

.forgejo/actions/setup-rust/action.yml

@@ -189,6 +189,13 @@ runs:
           cargo-binstall -y --no-symlinks timelord-cli
           echo "::endgroup::"
         fi
+        if command -v cargo-shear &> /dev/null; then
+          echo "✅ cargo-shear already available"
+        else
+          echo "::group::📦 Installing cargo-shear"
+          cargo binstall -y --no-symlinks cargo-shear
+          echo "::endgroup::"
+        fi
 
     - name: Configure sccache environment
       shell: bash
@@ -214,3 +221,4 @@ runs:
         echo "  Cargo: $(cargo --version)"
         echo "  prek: $(prek --version 2>/dev/null || echo 'installed')"
         echo "  timelord: $(timelord --version 2>/dev/null || echo 'installed')"
+        echo "  cargo-shear: $(cargo-shear --version 2>/dev/null || echo 'installed')"

.forgejo/workflows/prek-checks.yml

@@ -104,3 +104,6 @@ jobs:
             --profile test \
             --all-targets \
             --no-fail-fast
+
+      - name: Check for unused dependencies
+        run: cargo shear