Internal container nginx is now chain-aware: it prefers the outer proxy's
X-Forwarded-Proto/Host/Prefix and nests bundled sub-app prefixes under any
outer prefix (outer /ai + /township -> /ai/township). Fixes characters/
environments thumbnails and other absolute/sub-path URLs 404ing when the
all-in-one container runs behind a second reverse proxy. Documented the
required outer-proxy headers in docs/reverse-proxy-nginx.md.

LoRA training loads its base pipeline outside the model manager (and unloads
all manager models first), so the engine reported 0 loaded models mid-train.
Surface the active training base model via active_training_model() so the
engines card reflects the busy GPU.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RdMufYvtTbtGDWsiZVoXce