feat: Expose Caido proxy port to host for human-in-the-loop interaction

Users can now access the Caido web UI from their browser to inspect traffic,
replay requests, and perform manual testing alongside the automated scan.

- Map Caido port (48080) to a random host port in DockerRuntime
- Add caido_port to SandboxInfo and track across container lifecycle
- Display Caido URL in TUI sidebar stats panel with selectable text
- Bind Caido to 0.0.0.0 in entrypoint (requires image rebuild)
- Bump sandbox image to 0.1.12
- Restore discord link in exit screen

containers/docker-entrypoint.sh

@@ -9,7 +9,7 @@ if [ ! -f /app/certs/ca.p12 ]; then
   exit 1
 fi
 
-caido-cli --listen 127.0.0.1:${CAIDO_PORT} \
+caido-cli --listen 0.0.0.0:${CAIDO_PORT} \
           --allow-guests \
           --no-logging \
           --no-open \