Addresses #16283
Problem: TUI app-server permission approvals could drop filesystem
grants because request and response payloads were round-tripped through
mismatched camelCase and snake_case JSON shapes.
Solution: Replace the lossy JSON round-trips with typed app-server/core
permission conversions so requested and granted permission profiles,
including filesystem paths and scope, are preserved end to end.
This is a follow-up to https://github.com/openai/codex/pull/15922. That
previous PR deleted the old `tui` directory and left the new
`tui_app_server` directory in place. This PR renames `tui_app_server` to
`tui` and fixes up all references.
