Tufte 1.15.6

Community-directory review: !important usage audited against Obsidian's real app.css — 155 declarations reduced to 126. Removals proven visually lossless (4,100+ computed-style comparisons, desktop and phone viewports, light and dark). Every retained !important now carries a comment naming the specific competitor it must beat (app rules that are themselves !important, or inline styles set by Obsidian's JS, which selector specificity cannot override). No visual changes. Plugin zips unchanged.