Keep Panel settings text in place while the page opens by reserving the themed scrollbar gutter and excluding collapsed forms from width hints.

Strengthen the regression checks to compare multiple rendered frames on both axes, verify live RTL padding restoration, and enforce the strict no-skips gate for every QML runner invocation.

Documentation: update the usage and development guides, settings design record, and Unreleased changelog. No CLI contracts, configuration keys, translations, or TODO parity entries change.

Validation: strict make check passed with 878 Qt tests, 3 native label checks, 10 native geometry checks, and 62 Python tests. CI, packaging, and graphical smoke checks are recorded in PR #191. Review feedback and the reasons for retaining the stable gutter are documented in the PR.