A workspace per customer for support engineers

Customer #4729 files a ticket: a report is rendering wrong rows. On a normal SaaS, support pulls logs, asks the customer to repro, traces row IDs through a shared database trying to find theirs.

On a per-customer-container SaaS, support opens a workspace template that points at customer #4729's container. The workspace loads: a terminal in the customer's container, a SQLite browser pointed at their database file, a file manager showing their config, a browser panel showing the actual report URL the customer is looking at.

Support sees what the customer sees, in the customer's exact environment. They run the report in their terminal panel and watch it render in the browser panel. The bug repros the first time.