refactor(shared/ui): stop deep-importing sibling config/types (C-3)

Badge and TechText reached into $shared/ui/Label/config, and SearchBar into
$shared/ui/Input/types — bypassing the siblings public surface.

- Label/config.ts was explicitly shared text-styling config, not Labels
  internals; relocate it to shared/ui/labelConfig.ts (a neutral peer module)
  and point Label/Badge/TechText at it relatively.
- inputIconSize is a consumer-facing map; export it from Input/index.ts so
  SearchBar imports it through the barrel alongside Input.

src/shared/ui/labelConfig.ts

@@ -0,0 +1,34 @@
+/**
+ * Shared config.
+ * Import from here in each component to keep maps DRY.
+ */
+
+export type LabelFont = 'mono' | 'primary';
+
+export type LabelVariant =
+    | 'default'
+    | 'accent'
+    | 'muted'
+    | 'success'
+    | 'warning'
+    | 'error';
+
+export type LabelSize = 'xs' | 'sm' | 'md' | 'lg';
+
+export const labelSizeConfig: Record<LabelSize, string> = {
+    xs: 'text-4xs',
+    sm: 'text-3xs md:text-2xs',
+    md: 'text-2xs md:text-xs',
+    lg: 'text-sm',
+};
+
+export const labelVariantConfig: Record<LabelVariant, string> = {
+    default: 'text-neutral-900 dark:text-neutral-100',
+    accent: 'text-brand',
+    /* Light mode bumped from neutral-400 (~2.7:1 contrast, barely visible)
+       to neutral-600 (~7.5:1). Dark mode unchanged. */
+    muted: 'text-neutral-600 dark:text-neutral-500',
+    success: 'text-green-600 dark:text-green-400',
+    warning: 'text-yellow-600 dark:text-yellow-400',
+    error: 'text-brand',
+};