meshcoreMode partial was inside the generic .sidebar which gets hidden
when meshcore mode is active. Moved the include into meshcoreVisuals
(inside the output panel) — matching the same pattern as Meshtastic.
Also overrides mesh-visuals-container's column/padding defaults so the
meshcore sidebar+main row layout renders correctly.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>