fix cert and image display issues

docker/nginx/dev.conf

@@ -9,13 +9,39 @@
 #   - Frontend accessible on https://localhost (port 443)
 #   - Backend API on http://localhost:3001
 #   - Port 80 redirects to HTTPS
+#
+# IMPORTANT: Dual Hostname Configuration (localhost AND 127.0.0.1)
+# ============================================================================
+# The server_name directive includes BOTH 'localhost' and '127.0.0.1' to
+# prevent SSL certificate errors when resources use different hostnames.
+#
+# Problem Scenario:
+#   1. User accesses site via https://localhost/
+#   2. Database stores image URLs as https://127.0.0.1/flyer-images/...
+#   3. Browser treats these as different origins, showing ERR_CERT_AUTHORITY_INVALID
+#
+# Solution:
+#   - mkcert generates certificates valid for: localhost, 127.0.0.1, ::1
+#   - NGINX accepts requests to BOTH hostnames using the same certificate
+#   - Users can access via either hostname without SSL warnings
+#
+# The self-signed certificate is generated in Dockerfile.dev with:
+#   mkcert localhost 127.0.0.1 ::1
+#
+# This creates a certificate with Subject Alternative Names (SANs) for all
+# three hostnames, allowing NGINX to serve valid HTTPS for each.
+#
+# See also:
+#   - Dockerfile.dev (certificate generation, ~line 69)
+#   - docs/FLYER-URL-CONFIGURATION.md (URL configuration details)
+#   - docs/development/DEBUGGING.md (SSL troubleshooting)
 # ============================================================================
 
 # HTTPS Server (main)
 server {
     listen 443 ssl;
     listen [::]:443 ssl;
-    server_name localhost;
+    server_name localhost 127.0.0.1;
 
     # SSL Configuration (self-signed certificates from mkcert)
     ssl_certificate /app/certs/localhost.crt;
@@ -80,7 +106,7 @@ server {
 server {
     listen 80;
     listen [::]:80;
-    server_name localhost;
+    server_name localhost 127.0.0.1;
 
     return 301 https://$host$request_uri;
 }