Add local-first SPA architecture and containerized production deploy.

Move data access to use-cases and IndexedDB repositories with optional
remote fallback, changelog/sync ports, and encrypted local backup.
Add production Docker Compose (nginx frontend + optional backend) and
Apache host proxy configuration for deployment.

Co-authored-by: Cursor <cursoragent@cursor.com>

deploy/apache/social-graph.conf

@@ -0,0 +1,31 @@
+# Прокси на хосте → контейнеры Docker.
+# Скопировать:
+#   sudo cp deploy/apache/social-graph.conf /etc/apache2/sites-available/social-graph.conf
+#
+# Перед включением поднимите контейнеры:
+#   docker compose -f docker-compose.prod.yml --env-file deploy/.env.prod up -d frontend
+#   # при remote: ... --profile with-backend up -d
+#
+# sudo a2enmod proxy proxy_http headers rewrite
+# sudo a2ensite social-graph.conf
+# sudo apache2ctl configtest && sudo systemctl reload apache2
+
+<VirtualHost *:80>
+    ServerName your-domain.com
+    ServerAlias www.your-domain.com
+
+    ProxyPreserveHost On
+    RequestHeader set X-Forwarded-Proto "http"
+    RequestHeader set X-Forwarded-For %{REMOTE_ADDR}s
+
+    # Backend API (раскомментируйте при VITE_DATA_MODE=remote и profile with-backend)
+    # ProxyPass        /api http://127.0.0.1:8000/api
+    # ProxyPassReverse /api http://127.0.0.1:8000/api
+
+    # Frontend SPA (nginx в контейнере sg_frontend)
+    ProxyPass        / http://127.0.0.1:8080/
+    ProxyPassReverse / http://127.0.0.1:8080/
+
+    ErrorLog ${APACHE_LOG_DIR}/social-graph-error.log
+    CustomLog ${APACHE_LOG_DIR}/social-graph-access.log combined
+</VirtualHost>