diff --git a/.github/workflows/backend-ci.yml b/.github/workflows/backend-ci.yml
index 677e29d6..1bee0c55 100644
--- a/.github/workflows/backend-ci.yml
+++ b/.github/workflows/backend-ci.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/ci-performance.yml b/.github/workflows/ci-performance.yml
index d5699ebf..81e71113 100644
--- a/.github/workflows/ci-performance.yml
+++ b/.github/workflows/ci-performance.yml
@@ -10,7 +10,7 @@ jobs:
     name: Backend — lint, typecheck, test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
@@ -54,7 +54,7 @@ jobs:
     name: Frontend — build, lint, test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
@@ -101,7 +101,7 @@ jobs:
     name: Contracts — fmt, clippy, test, build WASM
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: dtolnay/rust-toolchain@stable
         with:
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 444d9f6e..4a873318 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3
@@ -42,7 +42,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/contract-abi-snapshot.yml b/.github/workflows/contract-abi-snapshot.yml
index 7d589ca7..29c0bf10 100644
--- a/.github/workflows/contract-abi-snapshot.yml
+++ b/.github/workflows/contract-abi-snapshot.yml
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Set up Rust
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/contract-fuzzing.yml b/.github/workflows/contract-fuzzing.yml
index 9ac816a5..d1466fc0 100644
--- a/.github/workflows/contract-fuzzing.yml
+++ b/.github/workflows/contract-fuzzing.yml
@@ -36,7 +36,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Rust
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/contract-upgrade-check.yml b/.github/workflows/contract-upgrade-check.yml
index d376c033..8efee221 100644
--- a/.github/workflows/contract-upgrade-check.yml
+++ b/.github/workflows/contract-upgrade-check.yml
@@ -20,13 +20,13 @@ jobs:
 
     steps:
       - name: Checkout PR branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           path: pr
           fetch-depth: 0
 
       - name: Checkout base branch (main)
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           ref: ${{ github.base_ref }}
           path: base
diff --git a/.github/workflows/contracts-ci.yml b/.github/workflows/contracts-ci.yml
index 7ec44b04..4e48cc4e 100644
--- a/.github/workflows/contracts-ci.yml
+++ b/.github/workflows/contracts-ci.yml
@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Rust
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index edb89ee6..6a361e60 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -20,7 +20,7 @@ jobs:
       pages_enabled: ${{ steps.pages_check.outputs.enabled }}
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Check if GitHub Pages is enabled
         id: pages_check
diff --git a/.github/workflows/format-check.yml b/.github/workflows/format-check.yml
index 0ff18d2c..6eefc285 100644
--- a/.github/workflows/format-check.yml
+++ b/.github/workflows/format-check.yml
@@ -9,7 +9,7 @@ jobs:
   prettier:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
diff --git a/.github/workflows/frontend-ci.yml b/.github/workflows/frontend-ci.yml
index d2c53564..17dfac05 100644
--- a/.github/workflows/frontend-ci.yml
+++ b/.github/workflows/frontend-ci.yml
@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
@@ -95,7 +95,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
@@ -167,7 +167,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/image-signing.yml b/.github/workflows/image-signing.yml
index 49afb609..bc225378 100644
--- a/.github/workflows/image-signing.yml
+++ b/.github/workflows/image-signing.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
diff --git a/.github/workflows/load-test.yml b/.github/workflows/load-test.yml
index d85eb9f4..0603aeeb 100644
--- a/.github/workflows/load-test.yml
+++ b/.github/workflows/load-test.yml
@@ -31,7 +31,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Install k6
         run: |
diff --git a/.github/workflows/mainnet-deploy.yml b/.github/workflows/mainnet-deploy.yml
index a57cc953..ef6ee133 100644
--- a/.github/workflows/mainnet-deploy.yml
+++ b/.github/workflows/mainnet-deploy.yml
@@ -12,7 +12,7 @@ jobs:
     name: Verify mainnet readiness checklist
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Confirm deploy intent
         run: |
@@ -38,6 +38,6 @@ jobs:
     runs-on: ubuntu-latest
     environment: mainnet
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - name: Deploy contracts
         run: echo "Deploy steps go here — gated on readiness-gate passing."
diff --git a/.github/workflows/monitoring-ci.yml b/.github/workflows/monitoring-ci.yml
index 398ecb6a..1b365d05 100644
--- a/.github/workflows/monitoring-ci.yml
+++ b/.github/workflows/monitoring-ci.yml
@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Install promtool
         run: |
diff --git a/.github/workflows/mutation-testing.yml b/.github/workflows/mutation-testing.yml
index 85108950..6ce11e91 100644
--- a/.github/workflows/mutation-testing.yml
+++ b/.github/workflows/mutation-testing.yml
@@ -22,7 +22,7 @@ jobs:
     name: cargo-mutants (rewards + campaign contracts)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Set up Rust toolchain
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/observability-ci.yml b/.github/workflows/observability-ci.yml
index bee496b1..bf7acdae 100644
--- a/.github/workflows/observability-ci.yml
+++ b/.github/workflows/observability-ci.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Install Prometheus (for promtool)
         run: |
@@ -40,7 +40,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
@@ -62,7 +62,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
diff --git a/.github/workflows/openapi-codegen.yml b/.github/workflows/openapi-codegen.yml
index 230a7588..e9a924e4 100644
--- a/.github/workflows/openapi-codegen.yml
+++ b/.github/workflows/openapi-codegen.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-node@v4
         with:
diff --git a/.github/workflows/openapi-validation.yml b/.github/workflows/openapi-validation.yml
index d75bc654..c128b503 100644
--- a/.github/workflows/openapi-validation.yml
+++ b/.github/workflows/openapi-validation.yml
@@ -18,7 +18,7 @@ jobs:
     name: Validate OpenAPI spec completeness
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: actions/setup-node@v4
         with:
           node-version: 20
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: validate-spec
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: actions/setup-node@v4
         with:
           node-version: 20
@@ -89,7 +89,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: validate-spec
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: actions/setup-node@v4
         with:
           node-version: 20
diff --git a/.github/workflows/performance-gate.yml b/.github/workflows/performance-gate.yml
index d53a4d4b..b484eaf3 100644
--- a/.github/workflows/performance-gate.yml
+++ b/.github/workflows/performance-gate.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v7
 
       - name: Setup Node.js
         uses: actions/setup-node@v3
@@ -53,7 +53,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v7
 
       - name: Setup Rust
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/python-sdk-ci.yml b/.github/workflows/python-sdk-ci.yml
index 14b43ac1..723e27b9 100644
--- a/.github/workflows/python-sdk-ci.yml
+++ b/.github/workflows/python-sdk-ci.yml
@@ -17,7 +17,7 @@ jobs:
         python-version: ['3.9', '3.11', '3.12']
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-python@v5
         with:
@@ -41,7 +41,7 @@ jobs:
       id-token: write # OIDC trusted publishing
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/setup-python@v5
         with:
diff --git a/.github/workflows/release-bindings.yml b/.github/workflows/release-bindings.yml
index 80008f62..be9e0f81 100644
--- a/.github/workflows/release-bindings.yml
+++ b/.github/workflows/release-bindings.yml
@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Rust (stable + wasm32 target)
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/repo-sanity.yml b/.github/workflows/repo-sanity.yml
index e16e2d32..9f1d1bc1 100644
--- a/.github/workflows/repo-sanity.yml
+++ b/.github/workflows/repo-sanity.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/reproducible-build.yml b/.github/workflows/reproducible-build.yml
index f150e9f2..33cb971d 100644
--- a/.github/workflows/reproducible-build.yml
+++ b/.github/workflows/reproducible-build.yml
@@ -15,7 +15,7 @@ jobs:
     
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
       
       - name: Install Rust toolchain (pinned)
         uses: dtolnay/rust-toolchain@stable
diff --git a/.github/workflows/sca-sbom.yml b/.github/workflows/sca-sbom.yml
index 0e80cd6c..52553496 100644
--- a/.github/workflows/sca-sbom.yml
+++ b/.github/workflows/sca-sbom.yml
@@ -20,7 +20,7 @@ jobs:
     name: cargo audit (Rust contracts)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Set up Rust toolchain
         uses: dtolnay/rust-toolchain@stable
@@ -42,7 +42,7 @@ jobs:
     name: cargo deny (license + advisory policy)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: EmbarkStudios/cargo-deny-action@v2
         with:
           log-level: warn
@@ -59,7 +59,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: [cargo-audit, cargo-deny]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/secrets-scan.yml b/.github/workflows/secrets-scan.yml
index c6fe80b6..6b2e2b46 100644
--- a/.github/workflows/secrets-scan.yml
+++ b/.github/workflows/secrets-scan.yml
@@ -14,7 +14,7 @@ jobs:
     name: Scan for secrets
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/security-headers-check.yml b/.github/workflows/security-headers-check.yml
index 9d12aa86..60829a54 100644
--- a/.github/workflows/security-headers-check.yml
+++ b/.github/workflows/security-headers-check.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/security-headers.yml b/.github/workflows/security-headers.yml
index e68c672f..ad490ee3 100644
--- a/.github/workflows/security-headers.yml
+++ b/.github/workflows/security-headers.yml
@@ -12,7 +12,7 @@ jobs:
     name: Verify security headers
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Start backend
         run: |
diff --git a/.github/workflows/testnet-integration.yml b/.github/workflows/testnet-integration.yml
index 9d182f61..494ac749 100644
--- a/.github/workflows/testnet-integration.yml
+++ b/.github/workflows/testnet-integration.yml
@@ -31,7 +31,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/visual-regression.yml b/.github/workflows/visual-regression.yml
index f529aa3e..5c2b4030 100644
--- a/.github/workflows/visual-regression.yml
+++ b/.github/workflows/visual-regression.yml
@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
         uses: actions/setup-node@v4