Add Makefile, package.json, and initial configuration for VitePress and Slidev integration

- Introduced a Makefile for streamlined commands related to building, running, and managing presentations.
- Created package.json to define project metadata, dependencies, and scripts for development and testing.
- Added .gitignore entries to exclude build artifacts and temporary files from version control.
- Included playwright.config.mjs for end-to-end testing setup with Playwright.
- Added README.md for project documentation, outlining setup instructions and development guidelines.

.github/workflows/build.yml

@@ -0,0 +1,40 @@
+# Vérifie que le build production (VitePress + Slidev) réussit sans lancer les E2E
+name: Build
+
+on:
+  push:
+    branches: [main, master, develop]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: build-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  production-build:
+    name: Build statique
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: npm
+
+      - run: npm ci
+
+      - name: Build (sync + VitePress + decks Slidev)
+        run: npm run build
+
+      - name: Tests layout dist/
+        run: node --test tests/dist-layout.test.mjs
+
+      - name: Archive dist/ (aperçu)
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/
+          retention-days: 3