Unified routing for policy-flagged content with active-target visibility

When a Secure LLM or on-premise model is configured and the administrator opts in, content that would otherwise be blocked for policy reasons is now redacted in place and routed to the configured target instead. The downstream model only ever receives placeholder tokens — raw sensitive content never leaves the gateway, regardless of which lane serves the reply.

The admin page at /admin/pii is consolidated into a single status view. It shows which target is currently serving flagged content, the priority order between the Secure LLM lane and the on-premise lane, and a master switch that disables the routing if either target is taken offline for maintenance. The badge shown to end users in chat matches the lane that actually served the reply.

No action required. The new routing is off until an administrator enables it.