Ajout de la traduction française à l'interface utilisateur.

- Création du fichier de traduction `fr.json` en se basant sur `en.json`.
- Mise à jour de la configuration i18n pour inclure la langue française.
- Modification du sélecteur de langue pour afficher l'option "Français" avec le drapeau correspondant.

jules-scratch/verification/verify_translation.py

@@ -0,0 +1,43 @@
+from playwright.sync_api import sync_playwright, expect
+import time
+
+def run(playwright):
+    browser = playwright.chromium.launch(headless=True)
+    context = browser.new_context()
+    page = context.new_page()
+
+    # Go to the page and wait for it to be ready
+    page.goto("http://localhost:5173", wait_until="networkidle")
+    print("Page loaded")
+
+    # The aria-label is in Chinese in the source, so we use that.
+    language_button = page.get_by_role("button", name="切换语言")
+
+    # Wait for the button to be visible
+    expect(language_button).to_be_visible()
+    print("Language button found")
+    language_button.click()
+    print("Language button clicked")
+
+    # Click the "Français" option
+    french_option = page.get_by_role("menuitem", name="Français")
+    expect(french_option).to_be_visible()
+    print("French option found")
+    french_option.click()
+    print("French option clicked")
+
+    # Wait for the language switch to apply
+    time.sleep(2)  # Wait for 2 seconds
+
+    # Now the aria-label should be in French
+    expect(page.get_by_role("button", name="Changer de langue")).to_be_visible(timeout=10000)
+    print("Language changed to French")
+
+    # Take a screenshot to see the page state
+    page.screenshot(path="jules-scratch/verification/verification.png")
+    print("Screenshot taken")
+
+    browser.close()
+
+with sync_playwright() as playwright:
+    run(playwright)