feat(v4.0): GitHub routes + CSRF exemptions for share/publish

- app/routers/github_routes.py: /api/github/status + disconnect
- CSRF: ajout /api/github, /api/pages, /api/recents aux exclusions
- main.py: registration github_router

app/main.py

@@ -15,6 +15,7 @@ from app.middleware.csrf import CSRFMiddleware
 from app.middleware.security import ContentSecurityPolicyMiddleware, RateLimitMiddleware
 from app.routers import dashboard, board, notes, api, auth, webhooks, collections, my_tasks, workspace, library, public_api, admin, sharing
 from app.routers.gitea import router as gitea_router
+from app.routers.github_routes import router as github_router
 from app.services.gitea_client import gitea
 from app.services.webhook_outbound import init_webhook_tables
 
@@ -65,6 +66,7 @@ app.include_router(workspace.router)
 app.include_router(library.router)
 app.include_router(admin.router)
 app.include_router(gitea_router)
+app.include_router(github_router)
 app.include_router(public_api.router)
 app.include_router(sharing.router)