feat: add MegaLinter workflow + hybrid test file

- .github/workflows/mega-linter.yml: analyzes MD/XML hybrid files
- test-hybride.md: sample file to test the workflow

Author: valorisa

.github/workflows/mega-linter.yml

@@ -0,0 +1,44 @@
+---
+name: MegaLinter
+
+on:
+  push:
+  pull_request:
+    branches: [main, master]
+
+env:
+  APPLY_FIXES: none
+
+concurrency:
+  group: ${{ github.ref }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+jobs:
+  megalinter:
+    name: MegaLinter
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: MegaLinter
+        uses: oxsecurity/megalinter/flavors/documentation@v9
+        env:
+          VALIDATE_ALL_CODEBASE: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          MARKDOWN_MARKDOWNLINT: true
+          XML_XMLLINT: true
+
+      - name: Archive production artifacts
+        if: success() || failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: MegaLinter-reports
+          path: |
+            megalinter-reports
+            mega-linter.log

test-hybride.md

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+# Test MegaLinter Hybride
+
+Ce fichier contient à la fois du Markdown et du XML.
+
+## Section Markdown
+
+Voici du texte en **gras**, en *italique*, et du `code`.
+
+### Liste Markdown
+- Item 1
+- Item 2
+- Item 3
+
+## Section XML
+
+Voici un bloc de code XML qui sera analysé par MegaLinter :
+
+```xml
+<root version="1.0">
+  <config>
+    <key name="test">valeur</key>
+    <item>élément 1</item>
+    <item>élément 2</item>
+  </config>
+</root>
+```
+
+## Autre bloc XML
+
+```xml
+<data>
+  <record id="1">
+    <field>Content here</field>
+  </record>
+</data>
+```
+
+---
+
+> Ce fichier est utilisé pour tester le workflow MegaLinter sur des fichiers hybrides MD/XML.