feat(timeline): خط روی دایره تمام می‌شود و کارت پایانی زیر آن می‌نشیند — لبهٔ بالای کارت دقیقاً روی نقطهٔ پایان خط (اندازه‌گیری DOM برای هر محتوا/اندازه)

frontend/src/components/home/Timeline.tsx

@@ -1,4 +1,4 @@
-import React, { useRef } from 'react'
+import React, { useLayoutEffect, useRef, useState } from 'react'
 import { motion, useScroll, useTransform, useInView } from 'framer-motion'
 import { useSite, type TimelineItem } from '../../api'
 import { useLang } from '../../i18n/lang'
@@ -9,17 +9,17 @@ const ease = [0.23, 1, 0.32, 1] as const
 
 type Milestone = TimelineItem
 
-function Item({ item, index, featured = false }: { item: Milestone; index: number; featured?: boolean }) {
-  const ref = useRef<HTMLLIElement>(null)
+function Item({ item, index, featured = false, onLi }: { item: Milestone; index: number; featured?: boolean; onLi?: (el: HTMLLIElement | null) => void }) {
+  const ref = useRef<HTMLLIElement | null>(null)
   const active = useInView(ref, { once: true, amount: 0.6 })
   const onRight = index % 2 === 0
 
   return (
-    <li ref={ref} className={`relative md:grid md:grid-cols-2 md:gap-16 ${featured ? 'mt-10 md:mt-16' : ''}`}>
+    <li ref={(el) => { ref.current = el; onLi?.(el) }} className={`relative md:grid md:grid-cols-2 md:gap-16 ${featured ? 'mt-10 md:mt-16' : ''}`}>
       {/* دایره‌ها: مرکز دایره در موبایل و دسکتاپ دقیقاً روی مرکز خط 2px است */}
       <span
         aria-hidden="true"
-        className={`absolute right-[-5px] top-1/2 z-10 -translate-y-1/2 h-3 w-3 rounded-full transition-all duration-500 ease-lux md:right-1/2 md:translate-x-1/2 ${
+        className={`absolute right-[-5px] z-10 -translate-y-1/2 h-3 w-3 rounded-full transition-all duration-500 ease-lux md:right-1/2 md:translate-x-1/2 ${featured ? 'top-0' : 'top-1/2'} ${
           active
             ? 'bg-copper shadow-[0_0_15px_rgba(197,143,92,0.6),0_0_0_6px_rgba(213,135,76,0.15)]'
             : 'bg-ivory/20'
@@ -56,12 +56,34 @@ export function Timeline() {
   const { timeline } = useSite()
   const { t } = useLang()
   const ref = useRef<HTMLOListElement>(null)
+  const lastLiRef = useRef<HTMLLIElement | null>(null)
+  // فاصلهٔ انتهای فهرست تا بالای کارت پایانی — خط دقیقاً روی بالای کارت تمام می‌شود
+  const [lineBottom, setLineBottom] = useState(0)
   const { scrollYProgress } = useScroll({
     target: ref,
-    offset: ['start 70%', 'end 100%'],
+    offset: ['start 70%', 'end 110%'],
   })
   const scaleY = useTransform(scrollYProgress, [0, 1], [0, 1])
 
+  useLayoutEffect(() => {
+    const measure = () => {
+      const ol = ref.current
+      const li = lastLiRef.current
+      if (!ol || !li) return
+      const gap = ol.getBoundingClientRect().bottom - li.getBoundingClientRect().top
+      setLineBottom(Math.max(0, Math.round(gap)))
+    }
+    measure()
+    const observer = new ResizeObserver(measure)
+    if (ref.current) observer.observe(ref.current)
+    if (lastLiRef.current) observer.observe(lastLiRef.current)
+    window.addEventListener('resize', measure)
+    return () => {
+      observer.disconnect()
+      window.removeEventListener('resize', measure)
+    }
+  }, [])
+
   return (
     <section className="bg-char py-24 md:py-32" aria-labelledby="timeline-title">
       <div className="mx-auto w-full max-w-site px-6 lg:px-10">
@@ -82,15 +104,16 @@ export function Timeline() {
             <span
               aria-hidden="true"
               className="absolute inset-y-0 right-0 w-[2px] bg-ivory/10 md:right-1/2 md:translate-x-1/2"
+              style={{ bottom: lineBottom }}
             />
             {/* خط متحرک - عرض 2px و همراستایی دقیق با مرکز */}
             <motion.span
               aria-hidden="true"
               className="absolute inset-y-0 right-0 w-[2px] origin-top bg-gradient-to-b from-copper/80 via-copper to-copper/55 shadow-[0_0_10px_rgba(197,143,92,0.5)] md:right-1/2 md:translate-x-1/2"
-              style={{ scaleY }}
+              style={{ scaleY, bottom: lineBottom }}
             />
             {timeline.map((item, i) => (
-              <Item key={item.id} item={item} index={i} featured={i === timeline.length - 1} />
+              <Item key={item.id} item={item} index={i} featured={i === timeline.length - 1} onLi={i === timeline.length - 1 ? (el) => { lastLiRef.current = el } : undefined} />
             ))}
           </ol>
           <div className="mt-12">