Constructor.
With project: overlay for project dirs; host / is read-only unless extra bind roots come from write_array. Without project: root read- only; cwd defaults to home.
| project |
Project folder, or null for no-project mode |
| allow_network |
Whether to allow network access (pass explicitly) |
| write_array |
Parsed allow_write tokens; never reparsed in #build_bubble_args / #can_write |