Three preview (render) bugs where DSH's chat-optimized markdown primitives
leak into the file-preview scroll world:
- CodeBlock banner: DSH's bannerWrap is position:sticky (top:0, z-index:6) so a
block keeps its copy action reachable inside a per-message scroll container.
In the preview every fence shares one .editorMd scroll container, so the
banner pins to the viewport top until the whole block scrolls past and reads
as a floating header. Neutralize stickiness for non-mermaid fences in the
preview (mermaid chrome replaces the banner and is excluded via
data-mermaid-processed).
- TOC popover z-index: .tocBar was z-index:3, below the code banner's 6, so the
outline panel painted beneath a sticky fence header. Raise the bar to 7.
- TOC dismissal: only the toggle re-click closed the popover. Add a document
pointerdown listener that closes on an outside press (blank preview space),
exempting the button and panel so the toggle still flips.
Adds md-toc unit coverage for outside-click dismiss and toggle-preserving
behavior; records the deviations in the TOC design doc.
Menghuan1918