feat: add GitHub repository dashboard with Prometheus metrics

ghtracker authenticates as a GitHub App and scans a configured list of repositories on a schedule. It serves a dashboard, a JSON state endpoint, a health probe and Prometheus metrics.

The dashboard lists only items that need attention: failing workflows, pull requests that wait too long or fail their checks, stale issues and projects that failed to scan. It has search, dynamic filters and a button that rescans on demand. The Vue app is embedded in the Go binary.

The client protects the GitHub rate limit with conditional requests, a request reserve and Retry-After handling.

src/components/ui/button/index.ts

@@ -0,0 +1,37 @@
+import type { VariantProps } from 'class-variance-authority'
+import { cva } from 'class-variance-authority'
+
+export { default as Button } from './Button.vue'
+
+export const buttonVariants = cva(
+  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-all disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg:not([class*='size-'])]:size-4 shrink-0 [&_svg]:shrink-0 outline-none focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-3 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive",
+  {
+    variants: {
+      variant: {
+        default: 'bg-primary text-primary-foreground hover:bg-primary/90',
+        destructive:
+          'bg-destructive text-white hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 dark:bg-destructive/60',
+        outline:
+          'border bg-background shadow-xs hover:bg-accent hover:text-accent-foreground dark:bg-input/30 dark:border-input dark:hover:bg-input/50',
+        secondary: 'bg-secondary text-secondary-foreground hover:bg-secondary/80',
+        ghost: 'hover:bg-accent hover:text-accent-foreground dark:hover:bg-accent/50',
+        link: 'text-primary underline-offset-4 hover:underline',
+      },
+      size: {
+        default: 'h-9 px-4 py-2 has-[>svg]:px-3',
+        xs: "h-6 gap-1 rounded-md px-2 text-xs has-[>svg]:px-1.5 [&_svg:not([class*='size-'])]:size-3",
+        sm: 'h-8 rounded-md gap-1.5 px-3 has-[>svg]:px-2.5',
+        lg: 'h-10 rounded-md px-6 has-[>svg]:px-4',
+        icon: 'size-9',
+        'icon-xs': "size-6 rounded-md [&_svg:not([class*='size-'])]:size-3",
+        'icon-sm': 'size-8',
+        'icon-lg': 'size-10',
+      },
+    },
+    defaultVariants: {
+      variant: 'default',
+      size: 'default',
+    },
+  },
+)
+export type ButtonVariants = VariantProps<typeof buttonVariants>