ci: Don't run clippy & tests if rust files haven't changed

.forgejo/workflows/prek-checks.yml

@@ -9,6 +9,7 @@ on:
 
 permissions:
   contents: read
+  pull-requests: read
 
 jobs:
   fast-checks:
@@ -40,10 +41,32 @@ jobs:
           cargo +nightly fmt --all -- --check && \
             echo "✅ Formatting check passed" || \
             exit 1
+  check-changes:
+    name: Check changed files
+    runs-on: ubuntu-latest
+    outputs:
+      rust: ${{ steps.filter.outputs.rust }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+        with:
+          persist-credentials: false
+
+      - name: Check for file changes
+        uses: https://github.com/dorny/paths-filter@v4
+        id: filter
+        with:
+          filters: |
+            rust:
+              - '**/*.rs'
+              - '**/Cargo.toml'
+              - '**/Cargo.lock'
 
   clippy-and-tests:
     name: Clippy and Cargo Tests
     runs-on: ubuntu-latest
+    needs: check-changes
+    if: needs.check-changes.outputs.rust == 'true'
 
     steps:
       - name: Checkout repository