✨ feat: Add token usage indicator to chat input

Add TokenUsageIndicator component with circular progress ring
Create useTokenUsage hook with Jotai atom for state
Add model context window lookups to data-provider
Consolidate token utilities (output limits, TOKEN_DEFAULTS)
Display input/output tokens and percentage of context used

client/src/components/Chat/Input/TokenUsageIndicator.tsx

@@ -0,0 +1,87 @@
+import { memo } from 'react';
+import { TooltipAnchor } from '@librechat/client';
+import { useTokenUsage } from '~/hooks';
+import { cn } from '~/utils';
+
+function formatTokens(n: number): string {
+  if (n >= 1000000) {
+    return `${(n / 1000000).toFixed(1)}M`;
+  }
+  if (n >= 1000) {
+    return `${(n / 1000).toFixed(1)}K`;
+  }
+  return n.toString();
+}
+
+const TokenUsageIndicator = memo(function TokenUsageIndicator() {
+  const { inputTokens, outputTokens, maxContext } = useTokenUsage();
+
+  const totalUsed = inputTokens + outputTokens;
+  const hasMaxContext = maxContext !== null && maxContext > 0;
+  const percentage = hasMaxContext ? Math.min((totalUsed / maxContext) * 100, 100) : 0;
+
+  // Ring calculations
+  const size = 28;
+  const strokeWidth = 2.5;
+  const radius = (size - strokeWidth) / 2;
+  const circumference = 2 * Math.PI * radius;
+  const offset = circumference - (percentage / 100) * circumference;
+
+  const tooltipText = hasMaxContext
+    ? `Input: ${formatTokens(inputTokens)} | Output: ${formatTokens(outputTokens)} | Max: ${formatTokens(maxContext)}`
+    : `Input: ${formatTokens(inputTokens)} | Output: ${formatTokens(outputTokens)} | Max: N/A`;
+
+  // Color based on percentage
+  const getProgressColor = () => {
+    if (!hasMaxContext) {
+      return 'stroke-text-secondary';
+    }
+    if (percentage > 90) {
+      return 'stroke-red-500';
+    }
+    if (percentage > 75) {
+      return 'stroke-yellow-500';
+    }
+    return 'stroke-green-500';
+  };
+
+  return (
+    <TooltipAnchor
+      description={tooltipText}
+      render={
+        <div className="flex size-9 items-center justify-center rounded-full p-1 transition-colors hover:bg-surface-hover">
+          <svg
+            width={size}
+            height={size}
+            viewBox={`0 0 ${size} ${size}`}
+            className="rotate-[-90deg]"
+          >
+            {/* Background ring */}
+            <circle
+              cx={size / 2}
+              cy={size / 2}
+              r={radius}
+              fill="transparent"
+              strokeWidth={strokeWidth}
+              className="stroke-border-medium"
+            />
+            {/* Progress ring */}
+            <circle
+              cx={size / 2}
+              cy={size / 2}
+              r={radius}
+              fill="transparent"
+              strokeWidth={strokeWidth}
+              strokeDasharray={circumference}
+              strokeDashoffset={hasMaxContext ? offset : circumference}
+              strokeLinecap="round"
+              className={cn('transition-all duration-300', getProgressColor())}
+            />
+          </svg>
+        </div>
+      }
+    />
+  );
+});
+
+export default TokenUsageIndicator;