feat(ui): cohesive frontend polish — design system + per-screen refinement

Distill the UI into a single, recognizable voice: a precision
instrument for one operator on one machine. Bloomberg-coded chrome,
warm-paper detail surfaces, mono-heavy numerics, with one editorial
serif accent for moments of weight.

Design system
- Three-font stack: Geist Sans (UI), Geist Mono (data), Instrument
  Serif (editorial display). No Inter, no system fonts.
- Two surfaces: dark chrome (--background, --accent, --signal) and
  warm paper detail surfaces (--surface, --surface-ink*).
- Inbox has its own Ticker Tape terminal palette (--tt-*).
- Shared component classes: .eyebrow, .mono, .display, .surface,
  .surface-2, .row-hover, .nav-active, .kbd, .editorial, .hairline.
- --m-* token aliases for the legacy drawer components so test-
  asserted class strings keep resolving to the same hue family.

Drawers (Claim + Remit)
- Editorial display face for totals (paid/adjustment amounts).
- Color-coded money tiles: green-tinted paid card, amber-tinted
  adjustment card when non-zero, muted otherwise.
- Tabs get accent-blue underline + CSS-driven active state.
- Validation banners with proper background opacity + ring-around-
  dot success badge.
- StateHistoryTimeline: dashed border, ring around dots, ↳ prefix
  for remit ids.
- DiagnosesList, PartiesGrid, MatchedRemitCard, CasAdjustmentsPanel:
  refined typography, dashed dividers, italic descriptions, mono
  amounts, font-semibold totals, hover row tints.

Inbox Ticker Tape
- Custom RowCheckbox with sr-only input + amber accent.
- Alternating row striping, hover tints, accent rail with inset
  shadow on selection.
- Refined sparkline with glow at high values.
- BulkBar: bottom-floating bar with amber count chip, larger shadow.
- CandidateBreakdown: animated progress bars with amber gradient.
- InboxHeader: Instrument Serif headline, mono day/date stamp,
  pulsing amber status dot.

Dialogs & search
- NewClaimDialog: editorial title, mono NPI/CPT/amount fields.
- SearchBar: refined input row with mono, footer with pulsing
  loading indicator.
- KeyboardCheatsheet: monogram icon chip, hover row states, refined
  eyebrow header.

Primitives
- StatusBadge / ClaimStateBadge: per-state dot indicators.
- SelectItem: data-[highlighted]:outline tokens for keyboard a11y.
- Table primitives: refined header treatment, hover/focus states.

Tests + build
- 354/354 tests passing across 59 files.
- Vite build clean (53.84 kB CSS / 560.86 kB JS).
- Eyebrow assertions updated to match the consolidated .eyebrow
  class (intact visual contract, abstracted class string).
- Badge variant tokens updated to the polished bg-muted/80 /
  /0.14 opacity scale.

src/components/Sparkline.tsx

@@ -1,14 +1,20 @@
 interface SparklineProps {
   values: number[];
   className?: string;
+  stroke?: string;
 }
 
 /**
- * Minimal SVG sparkline. Normalises to its own range, draws a stroked line
- * with a soft fill, and marks the last point. Stretch-friendly via
- * preserveAspectRatio="none" + non-scaling-stroke.
+ * Minimal SVG sparkline. Normalises to its own range, draws a stroked
+ * line with a soft fill, and marks the last point. Uses
+ * preserveAspectRatio="none" + non-scaling-stroke so the chart stretches
+ * with its container without distorting the stroke.
  */
-export function Sparkline({ values, className }: SparklineProps) {
+export function Sparkline({
+  values,
+  className,
+  stroke = "hsl(var(--accent))",
+}: SparklineProps) {
   if (!values || values.length < 2) return null;
   const w = 100;
   const h = 28;
@@ -37,11 +43,17 @@ export function Sparkline({ values, className }: SparklineProps) {
       height="36"
       aria-hidden="true"
     >
-      <path d={area} fill="hsl(var(--accent) / 0.13)" />
+      <defs>
+        <linearGradient id="sparkline-fill" x1="0" y1="0" x2="0" y2="1">
+          <stop offset="0%" stopColor={stroke} stopOpacity="0.18" />
+          <stop offset="100%" stopColor={stroke} stopOpacity="0" />
+        </linearGradient>
+      </defs>
+      <path d={area} fill="url(#sparkline-fill)" />
       <path
         d={line}
         fill="none"
-        stroke="hsl(var(--accent))"
+        stroke={stroke}
         strokeWidth="1.4"
         strokeLinecap="round"
         strokeLinejoin="round"
@@ -50,8 +62,8 @@ export function Sparkline({ values, className }: SparklineProps) {
       <circle
         cx={last[0]}
         cy={last[1]}
-        r="2"
-        fill="hsl(var(--accent))"
+        r="2.2"
+        fill={stroke}
         vectorEffect="non-scaling-stroke"
       />
     </svg>