In the Socials drawer, under the show/hide switch: text colour, an optional background plate
with its own colour and opacity, and a text drop shadow. The bar had been hard-wired
white-on-transparent since it shipped.
- `SocialsConfig` gains five additive properties (BarTextColor, BarBackgroundEnabled,
BarBackgroundColor, BarBackgroundOpacity, BarTextShadow).
- Persistence: five new Socials columns, added by the per-column idempotent migration pattern
(a half-migrated DB heals instead of failing), written in Save and read back in Load with
defaults for pre-existing rows.
- `SocialBarRenderer.Render(entries, SocialBarStyle?)` — the look is a separate value type so the
renderer stays a pure "entries + look" function and the preview can never read a half-applied
config mid-edit. A malformed hex falls back to white/black instead of throwing inside a render
tick.
- The plate hugs the entries (rounded 20px, padding) so it reads as a caption bar, not a band
across the frame. Off by default, because transparent is what creators have today.
- The colour pickers reuse `BorderColorPalette` — one catalogue of the app's colours, per the
TASK 60/63 rule.
Guard: SocialBarAppearanceTests paints the real strip and inspects pixels — default is white with
no plate, a red text colour reaches the glyphs, a 55% blue plate yields half-transparent blue
pixels, and the shadow adds dark pixels that were not there before.