feat(dashboard): widgets fit their content; wide screens get more grid columns (#5249)

Each widget is as tall as its content, never taller than its saved height
(where it scrolls). The dashboard is capped at 2400px instead of 1400px.
Past 12 columns' worth of width it adds columns (one per 110px, up to 24)
and places widgets again in reading order at their saved widths, so more sit
side by side instead of stretching. Edit mode shows and saves the
12-column layout, so a layout doesn't depend on the screen it was edited on.

The share view uses the same layout code (static/dash-layout.js).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

steward/static/steward.css

@@ -117,6 +117,9 @@ code { font-family: var(--fs-font-mono); font-size: 0.875em; background: var(--b
 
 /* Layout */
 main { padding: 1.5rem 2rem; max-width: 1400px; margin: 0 auto; width: 100%; min-width: 0; box-sizing: border-box; position: relative; z-index: 1; }
+/* The dashboard keeps a cap too, a wider one: past 12 columns' worth it adds
+   grid columns rather than stretching widgets (static/dash-layout.js). */
+main.main-wide { max-width: 2400px; }
 
 /* Responsive: sidebar slides off-canvas under 900px, toggled by ☰ */
 @media (max-width: 900px) {