minor #1097 Upgrade actions/checkout to v6 (OskarStark)

This PR was merged into the main branch.

Discussion
----------

 Upgrade `actions/checkout` to v6

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Docs?         | no
| Issues        | --
| License       | MIT

Commits
-------

cf88503 Upgrade actions/checkout to v6

Author: OskarStark

.github/workflows/deptrac.yaml

@@ -20,7 +20,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - name: Checkout
-              uses: actions/checkout@v5
+              uses: actions/checkout@v6
 
             - name: Configure environment
               run: |

.github/workflows/run-examples.yaml

@@ -18,7 +18,7 @@ jobs:
 
         steps:
             - name: Checkout code
-              uses: actions/checkout@v4
+              uses: actions/checkout@v6
 
             - name: Setup PHP
               uses: shivammathur/setup-php@v2

.github/workflows/validation.yaml

@@ -24,7 +24,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - name: Checkout
-              uses: actions/checkout@v5
+              uses: actions/checkout@v6
 
             - name: Validate store bridge naming conventions
               run: .github/scripts/validate-bridge-naming.sh store "src/store/src/Bridge/*" src/ai-bundle/config/options.php
@@ -34,7 +34,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - name: Checkout
-              uses: actions/checkout@v5
+              uses: actions/checkout@v6
 
             - name: Validate tool bridge naming conventions
               run: .github/scripts/validate-bridge-naming.sh tool "src/agent/src/Bridge/*"