v3.15.1

Fixed

• Editor screen was unusable in v3.15.0. The full-screen editor overlay stacked below the sticky dashboard header, which painted over the Save/Close row and panel tabs — nothing in the top band was visible or clickable. The overlay now stacks above all page chrome (and below modals).
• Hidden editor buttons actually hide. Preview CSS no longer shows for JS scripts; file-binding buttons only appear when relevant.

Changed

• Editor nav redesigned into one band: panel tabs (Code/Settings/Externals/Storage/Info) on the left, icon-only tools with tooltips on the right. Editor chrome is two slim rows; the code pane takes ~91% of the viewport at 1440x900.
• Save button is accented and fills while there are unsaved changes.

Internal

• New npm run smoke:editor harness drives the real editor in headless Chromium and hit-tests every control, so layering regressions fail loudly.