* feat(app): separate content typography from interface size
Readable prose benefits from its own scale without inflating navigation and controls. Preserve existing users’ rendered size during migration while giving fresh desktop installs a 15px content default.
* test(app): cover independent content typography
The appearance journey now verifies that changing interface size leaves content size intact. Timeline traversal yields when a test deliberately holds the requested page, so the helper no longer waits on its own gate.
* test(desktop): cover independent content typography
The desktop appearance regression follows the renamed Interface control and verifies it does not alter Content size.
