JS files: - ai.js: add t() import, replace 10 hardcoded French strings - sync.js: add t() import, replace 20 hardcoded French strings (toasts, status labels, events, AI panel) - graph.js: add t() import, replace 6 hardcoded French strings (tooltips, badges) Locales: - +36 new keys for ai.js, sync.js, graph.js - 1206 keys in each locale file (perfectly synchronized) - 0 French characters remaining in en.json Documentation: - README.fr.md created (French version) - ROADMAP.md point #63 updated to 100% complete