Add Dependabot and hash-pin GHA

.github/dependabot.yml

@@ -0,0 +1,26 @@
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/frontend"
+    schedule:
+      interval: "quarterly"
+    cooldown:
+      default-days: 7
+    groups:
+      # Batch low-risk minor/patch bumps into a single PR to cut review noise;
+      # major bumps open as individual PRs.
+      npm-minor-patch:
+        update-types:
+          - "minor"
+          - "patch"
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "quarterly"
+    cooldown:
+      default-days: 7
+    groups:
+      github-actions:
+        patterns:
+          - "*"

.github/workflows/benchmark.yml

@@ -42,10 +42,10 @@ jobs:
 
     steps:
     - name: Checkout memory tracker
-      uses: actions/checkout@v4
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c # v4.9.1
       with:
         python-version: '3.11'
 
@@ -111,7 +111,7 @@ jobs:
 
     - name: Upload benchmark results (if failed)
       if: failure()
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
       with:
         name: benchmark-logs
         path: |
@@ -121,7 +121,7 @@ jobs:
 
     - name: Upload benchmark results (on success)
       if: success()
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
       with:
         name: benchmark-results
         path: ./benchmark_results/

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
         with:
           fetch-depth: 0
       - name: Ensure lockfiles are updated when .in files change
@@ -45,7 +45,7 @@ jobs:
     name: Backend tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
         with:
           fetch-depth: 0
       - name: Check for backend changes
@@ -61,7 +61,7 @@ jobs:
           if echo "$CHANGED" | grep -Eq '^(backend/|\.github/workflows/ci\.yml$)'; then
             echo "backend=true" >> "$GITHUB_OUTPUT"
           fi
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         if: steps.changes.outputs.backend == 'true'
         with:
           python-version: "3.13"
@@ -87,8 +87,8 @@ jobs:
       run:
         working-directory: frontend
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
           node-version: 20
           cache: npm

.github/workflows/daily-benchmark.yml

@@ -57,10 +57,10 @@ jobs:
 
     steps:
     - name: Checkout memory tracker
-      uses: actions/checkout@v4
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c # v4.9.1
       with:
         python-version: '3.11'
 
@@ -151,7 +151,7 @@ jobs:
 
     - name: Upload benchmark results (if failed)
       if: failure()
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
       with:
         name: benchmark-logs-${{ matrix.build_config.binary_id }}
         path: |
@@ -161,7 +161,7 @@ jobs:
 
     - name: Upload benchmark results (on success)
       if: success()
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
       with:
         name: benchmark-results-${{ matrix.build_config.binary_id }}
         path: ./benchmark_results/