replace NPM with vanilla nginx + certbot

- nginx:alpine replaces nginx-proxy-manager
- certbot on host with standalone issuance and auto-renewal
- per-site nginx configs in conf.d/ (HTTP->HTTPS, bare->www)
- container names use underscores (timothykim_net)
- setup.sh: automated cert issuance, dynamic app startup
- deploy.sh: nginx -t guard, graceful image-not-found
- new-app.sh: Gitea API repo creation, nginx conf generation
- add ARCHITECTURE.md, USECASES.md, CLAUDE.md
- remove old NPM data/certs from tracking

docker/nginx/nginx.conf

@@ -0,0 +1,20 @@
+worker_processes auto;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include       /etc/nginx/mime.types;
+    default_type  application/octet-stream;
+    sendfile      on;
+    keepalive_timeout 65;
+
+    access_log /var/log/nginx/access.log;
+    error_log  /var/log/nginx/error.log;
+
+    add_header X-Content-Type-Options nosniff;
+    add_header X-Frame-Options DENY;
+
+    include /etc/nginx/conf.d/*.conf;
+}