Update dashboard community links to use env vars, add deploy configs

- Dashboard community links now use .env values like community page
- Removed hardcoded social media URLs from dashboard
- Added deploy folder with nginx and systemd service configs
- Moved linktree page to public route
- Various backend and auth context updates

deploy/spanglish_upstreams.conf

@@ -0,0 +1,7 @@
+upstream spanglish_frontend {
+    server 127.0.0.1:3019;
+}
+
+upstream spanglish_backend {
+    server 127.0.0.1:3018;
+}