fix: improve note interactions and markdown LaTeX support

## Bug Fixes

### Note Card Actions
- Fix broken size change functionality (missing state declaration)
- Implement React 19 useOptimistic for instant UI feedback
- Add startTransition for non-blocking updates
- Ensure smooth animations without page refresh
- All note actions now work: pin, archive, color, size, checklist

### Markdown LaTeX Rendering
- Add remark-math and rehype-katex plugins
- Support inline equations with dollar sign syntax
- Support block equations with double dollar sign syntax
- Import KaTeX CSS for proper styling
- Equations now render correctly instead of showing raw LaTeX

## Technical Details

- Replace undefined currentNote references with optimistic state
- Add optimistic updates before server actions for instant feedback
- Use router.refresh() in transitions for smart cache invalidation
- Install remark-math, rehype-katex, and katex packages

## Testing

- Build passes successfully with no TypeScript errors
- Dev server hot-reloads changes correctly

keep-notes/app/(auth)/forgot-password/page.tsx

@@ -0,0 +1,77 @@
+'use client'
+
+import { useState } from 'react'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Card, CardContent, CardDescription, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
+import { forgotPassword } from '@/app/actions/auth-reset'
+import { toast } from 'sonner'
+import Link from 'next/link'
+
+export default function ForgotPasswordPage() {
+  const [isSubmitting, setIsSubmitting] = useState(false)
+  const [isDone, setIsSubmittingDone] = useState(false)
+
+  const handleSubmit = async (e: React.FormEvent<HTMLFormElement>) => {
+    e.preventDefault()
+    setIsSubmitting(true)
+    const formData = new FormData(e.currentTarget)
+    const result = await forgotPassword(formData.get('email') as string)
+    setIsSubmitting(false)
+    
+    if (result.error) {
+      toast.error(result.error)
+    } else {
+      setIsSubmittingDone(true)
+    }
+  }
+
+  if (isDone) {
+    return (
+      <main className="flex items-center justify-center md:h-screen p-4">
+        <Card className="w-full max-w-[400px]">
+          <CardHeader>
+            <CardTitle>Check your email</CardTitle>
+            <CardDescription>
+              We have sent a password reset link to your email address if it exists in our system.
+            </CardDescription>
+          </CardHeader>
+          <CardFooter>
+            <Link href="/login" className="w-full">
+              <Button variant="outline" className="w-full">Return to Login</Button>
+            </Link>
+          </CardFooter>
+        </Card>
+      </main>
+    )
+  }
+
+  return (
+    <main className="flex items-center justify-center md:h-screen p-4">
+      <Card className="w-full max-w-[400px]">
+        <CardHeader>
+          <CardTitle>Forgot Password</CardTitle>
+          <CardDescription>
+            Enter your email address and we'll send you a link to reset your password.
+          </CardDescription>
+        </CardHeader>
+        <form onSubmit={handleSubmit}>
+          <CardContent className="space-y-4">
+            <div className="space-y-2">
+              <label htmlFor="email" className="text-sm font-medium">Email</label>
+              <Input id="email" name="email" type="email" required placeholder="name@example.com" />
+            </div>
+          </CardContent>
+          <CardFooter className="flex flex-col gap-4">
+            <Button type="submit" className="w-full" disabled={isSubmitting}>
+              {isSubmitting ? 'Sending...' : 'Send Reset Link'}
+            </Button>
+            <Link href="/login" className="text-sm text-center underline">
+              Back to login
+            </Link>
+          </CardFooter>
+        </form>
+      </Card>
+    </main>
+  )
+}