v1.6.1: theming covers the whole diagram

Fixed

• Theming now re-skins the whole diagram, not just the tables. A custom truss.theme palette previously left the relationship lines and labels, the label backdrop, the background grid, and (in dark mode) the odd table rows and input backgrounds on the shipped Blueprint colours, so a themed diagram showed blue lines and mismatched rows. The background, surface, and muted knobs now also drive the label, row, and input tokens, and the background grid is derived as a faint tint of the accent colour, so a few knob values re-skin the diagram completely.