Added Github API rate limiting

- Implemented comprehensive GitHub API rate limit handling:
    - Integrated @octokit/plugin-throttling for automatic retry with exponential backoff
    - Added RateLimitManager service to track and enforce rate limits
    - Store rate limit status in database for persistence across restarts
    - Automatic pause and resume when limits are exceeded
    - Proper user identification for 5000 req/hr authenticated limit (vs 60 unauthenticated)

  - Improved rate limit UI/UX:
    - Removed intrusive rate limit card from dashboard
    - Toast notifications only at critical thresholds (80% and 100% usage)
    - All rate limit events logged for debugging

  - Optimized for GitHub's API constraints:
    - Reduced default batch size from 10 to 5 repositories
    - Added documentation about GitHub's 100 concurrent request limit
    - Better handling of repositories with many issues/PRs

src/components/ui/progress.tsx

@@ -0,0 +1,30 @@
+import * as React from "react"
+import * as ProgressPrimitive from "@radix-ui/react-progress"
+
+import { cn } from "@/lib/utils"
+
+interface ProgressProps extends React.ComponentPropsWithoutRef<typeof ProgressPrimitive.Root> {
+  indicatorClassName?: string
+}
+
+const Progress = React.forwardRef<
+  React.ElementRef<typeof ProgressPrimitive.Root>,
+  ProgressProps
+>(({ className, value, indicatorClassName, ...props }, ref) => (
+  <ProgressPrimitive.Root
+    ref={ref}
+    className={cn(
+      "relative h-4 w-full overflow-hidden rounded-full bg-secondary",
+      className
+    )}
+    {...props}
+  >
+    <ProgressPrimitive.Indicator
+      className={cn("h-full w-full flex-1 bg-primary transition-all", indicatorClassName)}
+      style={{ transform: `translateX(-${100 - (value || 0)}%)` }}
+    />
+  </ProgressPrimitive.Root>
+))
+Progress.displayName = ProgressPrimitive.Root.displayName
+
+export { Progress }