p2 layout

- _tokens.scss — added --wg-space-2xs…xl (0.25–2rem, 4pt scale), --wg-ledger-line: 1.78rem, --wg-page-width: 1420px.
- Card gaps unified to --wg-space-sm, card interiors to --wg-space-md, the compact topic-list header to --wg-space-xs (_categories.scss, _topics.scss, _widgets.scss, _responsive.scss).
- Ledger ruling height is now one token across topics, posts, pagination, quick-reply, and the composer (_posts.scss, _controls.scss).
- Footer rails now share the topbar's 1420px measure (_footer.scss:36,123,143), so the page's top and bottom edges align.
- Stat tiles got explicit padding instead of inheriting Bootstrap's (_topics.scss:369, _categories.scss:326).
- Documented the scale and rules in DESIGN.md (new "Spacing & Layout" section).

DESIGN.md

@@ -38,6 +38,13 @@ typography:
     fontWeight: 400
 rounded:
   md: "8px"
+spacing:
+  2xs: "0.25rem"
+  xs: "0.5rem"
+  sm: "0.75rem"
+  md: "1rem"
+  lg: "1.5rem"
+  xl: "2rem"
 components:
   button-primary:
     backgroundColor: "#5a4a1a"
@@ -122,6 +129,16 @@ A tarnish-and-decay palette: gold that has aged, plum that has bruised, black th
 ### Named Rules
 **The Engraving Rule.** Wide letter-spacing and uppercase belong only to small Cinzel labels. Headings at reading size keep letter-spacing 0. Body text is never tracked, never uppercase.
 
+## 3½. Spacing & Layout
+
+Tokens in `_tokens.scss`: `--wg-space-2xs/xs/sm/md/lg/xl` (0.25 / 0.5 / 0.75 / 1 / 1.5 / 2rem, a 4pt scale). Surface-level rules:
+
+- Card interiors pad `--wg-space-md`; compact control bars (topic-list header) pad `--wg-space-xs`.
+- Gaps between sibling cards/widgets are `--wg-space-sm`; below `lg` card padding also drops to `--wg-space-sm`.
+- The ledger ruling row height is one token everywhere: `--wg-ledger-line` (1.78rem).
+- Page rails (topbar, footer, content) share `--wg-page-width` (1420px).
+- Fine optical values (tag chips, badge padding, etched insets) stay hand-tuned; the scale governs surface-level spacing, not micro-typography.
+
 ## 4. Elevation
 
 Shadows here are candlelight, not physics. They set mood — a soft top highlight like sheen on fabric, an inner plum glow, a wide black falloff — and they do not communicate stacking. Hierarchy between surfaces is carried by panel tone (Velvet Panel Deep → Velvet Panel → Velvet Panel Raised) and by border strength (gold at 8% → 14% → 18–22% alpha).