Add PUBLIC_URL environment variable for shared documents

The Problem Currently, Outline uses a single URL environment variable for everything - both the main app and shared documents. This creates issues when organizations want to: • Keep internal workspaces private while sharing some docs publicly • Use different domains like docs.company.com for public content and internal.company.com for the main app • Route traffic differently (CDN for public docs, VPN for internal access) Right now, if I want this setup, I have to run two separate Outline instances, which is way more complex than needed. What I'm Suggesting Add an optional PUBLIC_URL environment variable that only affects shared document routes (/s/:shareId and /s/:shareId/doc/:slug). Example setup: What changes: • Shared links would generate as • Main app stays at • If PUBLIC_URL isn't set, everything works exactly like today Why This Helps 1. Security: Keep your workspace internal, share docs publicly 2.…