Adjust visual styling in web/linker.js to create a more compact, consistent UI. Reduces paddings, margins, gaps and font sizes across cards, rows, tabs and controls; tweaks border radii, shadows and combo/list dimensions. Introduces a new .ml-btn-ghost variant (and applies it to Link/Locate/Refresh buttons) for a subtle button appearance, and updates confidence badge colors/borders for clearer visual hierarchy. Overall changes aim to tighten spacing and harmonize button/badge styling for improved readability and consistency.