fix(auth): trim whitespace from CCR_APP_URL to prevent sign-in issues

docs: DEPLOY.md - persistence caveat resolved (Postgres + R2 live, verified)

Deploy doc: split Space Variables from Secrets

Upload limits: make the byte ceiling configurable and stream-checked

Persistent storage: DATABASE_URL (Postgres/Supabase) support + deploy steps

Add /guide tester page and /samples demo-data downloads

Fix formatting in DEPLOY.md for better readability of space secrets

Sync platform from lab mainline: dev instance ready to deploy

CCR Platform: web platform for Contextualized Construct Representations