MainViewModel.Socials.cs: social-bar state (_socials/_socialBarFrame/
_socialValidator), bar props (HasSocials/SocialBarVisible/SocialBarDotBrush/
SocialBarGlowBrush/Socials/SocialBarTop), OpenSocialDialog + NotifySocialsChanged
+ RenderSocialBarFrame (SocialBarRenderer), fediverse heal
(HealFediverseSoftwareAsync/HealFediverseSoftwareInBackground),
SetSocialBarPosition/ToggleSocialBarPosition, OpenSocialDialogCommand.
BarOnBrush/BarOffBrush/CreateBrush stay in core (shared tokens used by
Audio/Trax partials); core keeps ctor command assignment, LoadLayout,
SaveLayoutNow, and the compositor socialBar seam.
Docs: index.md restructured — each landed partial (Account..Trax) now owns its
own table row, the core row shrinks to only what remains in MainViewModel.cs,
and the split tracker is a compact code<->commit map.
Verify: 0 warnings, 246 passed, 2 known failures only.
