* fix(mcp): make Add Server + Catalog headers read distinctly from buttons
Both section headers reused the shared SectionHeader, which paints the
title in primary/bold — so each header row looked like a tappable
button next to its trailing TextButton. Add a scoped McpSectionHeader
with a distinct leading icon (➕ Add / 🗄 Explore) and a neutral
onSurface bold title, so they read as headers and look different
from each other.
* fix(mcp): give section header row + action button distinct backgrounds
- Whole header row now sits on a surfaceContainerLow rounded (12dp) surface
so it reads as a contained section header, not bare text.
- The trailing New/Browse action uses secondaryContainer (onSecondaryContainer
text) — a clearly different color from the row background, so button
vs header are visually distinct.
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Co-authored-by: M57 <hy4ri@users.noreply.github.com>
