Add typography roles, text primitives, fontkit measurer and layout lint

Txt always sets an absolute line height; RenderTxt never does. Row pins
every cell and stacks when the fill column would be too narrow. IdText and
FitText shrink then chunk or truncate. The fontkit measurer matches react-pdf
text widths exactly. A TypeScript-AST lint test enforces the layout rules
(no lineHeight outside Txt, no non-literal fixed/wrap/minPresenceAhead,
flexGrow needs flexBasis, no stray absolute positioning).

src/pdf/blocks/Tracked.tsx

@@ -0,0 +1,25 @@
+import { roleToken } from "../fonts/roles";
+import { Txt, type TxtProps } from "./Txt";
+
+export interface TrackedProps extends Omit<TxtProps, "align"> {
+  align: "right" | "center";
+}
+
+/**
+ * textkit adds letterSpacing after every glyph, the last one included, so right- and centre-aligned
+ * tracked text sits one tracking step too far left. This cancels it with a negative margin: the full
+ * step on the right edge for `right`, half a step each side for `center` (shifting the box right by
+ * half a step).
+ *
+ * HAZARD: the Text box now overhangs its parent by up to one tracking step. Overflow and safe-zone
+ * audits must measure ink (glyph extents), not boxes, or they flag it.
+ */
+export function Tracked({ align, style, ...rest }: TrackedProps) {
+  const token = roleToken(rest.role);
+  const step = (token.tracking ?? 0) * token.size;
+  const margin =
+    align === "right"
+      ? { marginRight: -step }
+      : { marginLeft: step / 2, marginRight: -step / 2 };
+  return <Txt {...rest} align={align} style={{ ...margin, ...style }} />;
+}