chore(ts-migration): migrate UI primitives and design system to TypeScript

Phase 6. 57 files: 23 vendored shadcn primitives, 30 design-system components,
4 charts. Plus `src/components/ds/props.ts`, which is types only.

Renaming these alone took typecheck from 37 to 1008, and the reason is worth
recording because it is the shape of every remaining phase.

These components had NO prop contract. No PropTypes, no validation: in the
JavaScript every prop was optional and every extra prop was spread onto the
underlying element. TypeScript infers a destructured parameter WITHOUT a default
as REQUIRED, so the moment the files became `.tsx` it invented a rule the
components never had and rejected several hundred call sites that have always
worked. That is the compiler describing its own inference, not a defect it
found.

Three mechanical fixes, each restoring a contract that already existed:

  - 57 JSDoc `@type {React.ForwardRefExoticComponent<any>}` annotations become
    real TypeScript annotations. Those comments were the previous authors'
    deliberate compatibility types; JSDoc stops applying in a `.tsx` file, so
    converting them preserves an intent that was already written down.

  - 61 `React.forwardRef(...)` calls gain `<any, any>`. Without generics `ref`
    infers `ForwardedRef<unknown>`, which no element's `Ref<T>` accepts - so
    every primitive that forwards a ref to a `div` failed on the ref, not the
    props.

  - 78 component signatures take `DsProps`, a documented alias for
    `Record<string, any>`. It exists so the decision is recorded once and is
    greppable when someone tightens it, rather than being 78 bare `any`s with
    no explanation between them. The prop NAMES are not lost: every component
    still destructures them by name, which is where a reader looks.

Four files needed real types rather than compatibility ones. `ds/toast` takes
react-hot-toast's own `ToastOptions`, which narrows `position` to its
`ToastPosition` union instead of widening to `string` - the widening was what
made all six calls unassignable. `ds/Pagination`'s page range is genuinely
`(number | string)[]`, because it interleaves page numbers with '…' markers that
the renderer tests for. `ds/Field` narrows `children.props` at three reads, and
`ds/Avatar` needed the ref generic.

Two of my own automated passes were wrong and were caught rather than shipped. A
props-interface generator dropped alternating props, because non-overlapping
regex matches consume the separating comma - it made things worse (83 file
errors to 146) and was reverted wholesale. A second pass missed every
multi-line signature whose defaults contain a `)`, such as `onClose = () => {}`;
that needed a brace matcher rather than a character class.

56 of 57 files emit byte-identical JavaScript. The one exception is `ds/toast`,
where a JSDoc type CAST - `/** @type {ToastPosition} */ ('bottom-center')` -
became a real annotation, so the emitted output loses a comment and a pair of
now-redundant parentheses. The value is `"bottom-center"` either way; the
minified outputs differ only in esbuild's choice of mangled local names.

Verified: tsc 37 -> 35, set-difference showing zero introduced and two removed;
zero errors remain in any Phase 6 file; npm test 1684/1691 with the same seven
failures; lint 0 errors; build succeeds with the API origin inlined; baseline
artifacts untouched.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HBG1wnuRfJKCstGB8Fekr8

src/components/ds/ChartContainer.tsx

@@ -0,0 +1,175 @@
+import type { DsProps } from './props';
+import * as React from 'react';
+import { ResponsiveContainer } from 'recharts';
+import { cn } from '@/lib/utils';
+import { Surface } from '@/components/ds/Surface';
+import { SectionHeader } from '@/components/ds/SectionHeader';
+import { EmptyState } from '@/components/ds/EmptyState';
+import { SkeletonChart } from '@/components/ds/Skeleton';
+import { BarChart3 } from 'lucide-react';
+
+/**
+ * The chart palette. Recharts needs literal colours, not Tailwind classes, so
+ * the brand values are mirrored here — this array is the only place a chart
+ * should get a colour from.
+ */
+export const CHART_COLORS = ['#0838E0', '#F9E547', '#333F48', '#F8E08E', '#D1E0D7', '#062BAF'];
+
+export const CHART_TONES = {
+  brand: '#0838E0',
+  brandDark: '#062BAF',
+  accent: '#F9E547',
+  accentPale: '#F8E08E',
+  navy: '#333F48',
+  mint: '#D1E0D7',
+  grid: 'hsl(150 8% 87%)',
+  axis: 'hsl(220 9% 64%)',
+};
+
+/** Shared axis props so every chart's ticks match. */
+export const AXIS_PROPS = {
+  stroke: CHART_TONES.axis,
+  tick: { fontSize: 11, fill: CHART_TONES.axis },
+  tickLine: false,
+  axisLine: false,
+};
+
+/**
+ * A tooltip matching the design system's surfaces. Recharts' default is a plain
+ * white box that ignores the token set.
+ */
+/** @param {any} props */
+export function ChartTooltip({ active, payload, label, valueFormatter, labelFormatter }: DsProps) {
+  if (!active || !payload?.length) return null;
+
+  return (
+    <div className="rounded-xl border border-border bg-surface px-3 py-2 shadow-lg">
+      {label != null && (
+        <p className="text-caption font-semibold text-ink-1 mb-1">
+          {labelFormatter ? labelFormatter(label) : label}
+        </p>
+      )}
+      <div className="space-y-0.5">
+        {payload.map((entry, i) => (
+          <div key={i} className="flex items-center gap-2 text-caption">
+            <span
+              className="w-2 h-2 rounded-full shrink-0"
+              style={{ backgroundColor: entry.color || entry.fill }}
+              aria-hidden="true"
+            />
+            <span className="text-ink-3">{entry.name}</span>
+            <span className="ml-auto font-semibold text-ink-1 tabular-nums">
+              {valueFormatter ? valueFormatter(entry.value) : entry.value}
+            </span>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}
+
+/**
+ * A legend that reads as part of the card rather than as chart furniture.
+ * Items: `{ label, color, value? }`.
+ */
+export function ChartLegend({ items = [], className }: DsProps) {
+  return (
+    <div className={cn('flex flex-wrap items-center gap-x-4 gap-y-2', className)}>
+      {items.map((item) => (
+        <div key={item.label} className="flex items-center gap-1.5">
+          <span
+            className="w-2.5 h-2.5 rounded-sm shrink-0"
+            style={{ backgroundColor: item.color }}
+            aria-hidden="true"
+          />
+          <span className="text-caption text-ink-3">{item.label}</span>
+          {item.value != null && (
+            <span className="text-caption font-semibold text-ink-1 tabular-nums">{item.value}</span>
+          )}
+        </div>
+      ))}
+    </div>
+  );
+}
+
+/**
+ * ChartContainer — the card a chart lives in.
+ *
+ * Owns the title row, the fixed plot height, the loading skeleton, the empty
+ * state, and an optional headline figure. Charts inside it are pure Recharts
+ * children, so swapping a bar chart for a line chart changes nothing else.
+ */
+/** @param {any} props */
+export function ChartContainer({
+  title,
+  subtitle,
+  icon,
+  /** A big number in the top-right — an average, a total. */
+  headline,
+  headlineLabel,
+  /** Right-aligned controls, e.g. a SegmentedToggle for the range. */
+  actions,
+  legend,
+  height = 260,
+  loading = false,
+  isEmpty = false,
+  emptyMessage = 'No data for this period',
+  children,
+  /** Skips ResponsiveContainer for children that are not Recharts charts. */
+  raw = false,
+  footer,
+  className,
+}: DsProps) {
+  if (loading) return <SkeletonChart className={className} height={height} />;
+
+  return (
+    <Surface radius="xl" padding="lg" className={cn('flex flex-col', className)}>
+      {(title || headline || actions) && (
+        <div className="flex items-start justify-between gap-4 mb-1">
+          <div className="min-w-0 flex-1">
+            {title && (
+              <SectionHeader
+                title={title}
+                subtitle={subtitle}
+                icon={icon}
+                className={cn(subtitle ? 'mb-0' : 'mb-0')}
+              />
+            )}
+          </div>
+
+          <div className="flex items-start gap-3 shrink-0">
+            {actions}
+            {headline != null && (
+              <div className="text-right">
+                <div className="text-title-lg font-heading font-bold text-krow-blue tabular-nums leading-none">
+                  {headline}
+                </div>
+                {headlineLabel && (
+                  <div className="text-[10px] uppercase tracking-wide text-ink-4 mt-1">
+                    {headlineLabel}
+                  </div>
+                )}
+              </div>
+            )}
+          </div>
+        </div>
+      )}
+
+      {legend && <ChartLegend items={legend} className="mb-4 mt-3" />}
+
+      <div className={cn('flex-1 min-w-0', !legend && 'mt-4')} style={{ minHeight: height }}>
+        {isEmpty ? (
+          <EmptyState icon={BarChart3} variant="filtered" title="Nothing to chart" description={emptyMessage} size="sm" />
+        ) : raw ? (
+          children
+        ) : (
+          <ResponsiveContainer width="100%" height={height}>
+            {children}
+          </ResponsiveContainer>
+        )}
+      </div>
+
+      {footer && <div className="mt-4 pt-4 border-t border-border">{footer}</div>}
+    </Surface>
+  );
+}