fix: container orchestration stability, AIUI inclusion, lnd-ui port, version 1.3.0

Container stability:
- Merge scan results instead of full replacement (prevents UI flapping)
- Absence threshold: 3 consecutive missed scans before removing from state
- container-list RPC uses cached scanner state for consistency
- Increased Podman API timeout 30s → 60s (scanner + health monitor)
- Keep crashed containers visible as "exited" instead of podman rm -f
- Resolve host-gateway IP via ip route (podman 4.3.x compatibility)

ISO build fixes:
- AIUI web app inclusion: searches 5 paths + CI step to copy from build server
- Claude API proxy: systemctl enable with symlink fallback
- AIUI nginx: try_files =404 (was /aiui/index.html redirect loop)
- Build version set to 1.3.0

Container fixes:
- lnd-ui: nginx listens on 8080 (was 80, Permission denied in rootless)
- first-boot: image-versions.sh sourced from correct path with validation
- first-boot: host-gateway resolved to actual gateway IP

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/docker/nginx-demo.conf

@@ -75,7 +75,7 @@ http {
         # Serve AIUI SPA
         location /aiui/ {
             alias /usr/share/nginx/html/aiui/;
-            try_files $uri $uri/ /aiui/index.html;
+            try_files $uri $uri/ =404;
 
             location ~* /aiui/assets/ {
                 expires 1y;