Docker HTTPS by default, smoke test improvements

Docker:
- HTTPS enabled by default (generates self-signed cert)
- Added docker-entrypoint.sh for SSL cert generation
- Gunicorn now starts with --certfile/--keyfile when HTTPS enabled
- Install curl/openssl in web container for healthcheck and certs
- Updated docs to reflect HTTPS default

Smoke Test:
- Moved from rpi/ to scripts/ (works for Pi, Docker, and dev)
- Updated header and examples
- Added to .gitignore exceptions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/web/docker-entrypoint.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+#
+# Docker entrypoint for Stegasoo Web UI
+# Handles SSL certificate generation and gunicorn startup
+#
+
+set -e
+
+CERT_DIR="/app/frontends/web/certs"
+CERT_FILE="$CERT_DIR/cert.pem"
+KEY_FILE="$CERT_DIR/key.pem"
+HOSTNAME="${STEGASOO_HOSTNAME:-localhost}"
+
+# Generate self-signed SSL certificate if HTTPS enabled and certs don't exist
+generate_certs() {
+    if [ ! -f "$CERT_FILE" ] || [ ! -f "$KEY_FILE" ]; then
+        echo "Generating self-signed SSL certificate for $HOSTNAME..."
+        mkdir -p "$CERT_DIR"
+
+        openssl req -x509 -newkey rsa:2048 \
+            -keyout "$KEY_FILE" \
+            -out "$CERT_FILE" \
+            -sha256 -days 365 -nodes \
+            -subj "/CN=$HOSTNAME" \
+            -addext "subjectAltName=DNS:$HOSTNAME,DNS:localhost,IP:127.0.0.1" \
+            2>/dev/null
+
+        echo "SSL certificate generated."
+    else
+        echo "Using existing SSL certificates."
+    fi
+}
+
+# Start gunicorn with appropriate settings
+if [ "${STEGASOO_HTTPS_ENABLED:-false}" = "true" ]; then
+    echo "HTTPS mode enabled"
+    generate_certs
+
+    exec gunicorn \
+        --bind 0.0.0.0:5000 \
+        --workers 2 \
+        --threads 4 \
+        --timeout 120 \
+        --certfile "$CERT_FILE" \
+        --keyfile "$KEY_FILE" \
+        app:app
+else
+    echo "HTTP mode (HTTPS disabled)"
+    exec gunicorn \
+        --bind 0.0.0.0:5000 \
+        --workers 2 \
+        --threads 4 \
+        --timeout 120 \
+        app:app
+fi