fix: 双栏非对称吸底滚动与对齐

- 去掉首页侧栏额外 padding，左右两栏初始顶部对齐
- 隐藏 #page-scroll 滚动条
- 左侧到底后用 translateY 补偿吸附在视口底部，右侧继续滚动；右侧先到底时两栏同步
- ResizeObserver 重算吸附阈值
- 验证：初始 top 148/148；滚动后左栏 top 144 固定、bottom 900；无滚动条

stash-web/src/App.css

@@ -1299,6 +1299,21 @@ a.entry-href:hover {
   min-width: 0;
 }
 
+/* 首页：左右栏共用一个滚动区，左侧到底后吸底 */
+#page-scroll {
+  scrollbar-width: none;
+  -ms-overflow-style: none;
+}
+
+#page-scroll::-webkit-scrollbar {
+  display: none;
+}
+
+.sidebar-home {
+  padding-top: 0;
+  will-change: transform;
+}
+
 .sidebar-divider {
   margin: var(--su-space-2) 0;
   border-top: 1px dashed var(--su-border-strong);

stash-web/src/AppNext.tsx

@@ -216,14 +216,33 @@ export default function AppNext() {
     if (sider instanceof HTMLElement) {
       sider.style.overflow = 'visible'
       sider.style.height = 'auto'
+      sider.style.alignSelf = 'flex-start'
     }
 
     const onScroll = () => setScrolled(body.scrollTop > 4)
+    const updateSticky = () => {
+      const viewport = body.clientHeight
+      const maxLeft = Math.max(0, sider instanceof HTMLElement ? sider.offsetHeight - viewport : 0)
+      const offset = Math.max(0, body.scrollTop - maxLeft)
+      if (sider instanceof HTMLElement) {
+        sider.style.transform = offset > 0 ? `translateY(${offset}px)` : ''
+      }
+    }
+
     body.addEventListener('scroll', onScroll, { passive: true })
+    body.addEventListener('scroll', updateSticky, { passive: true })
+    window.addEventListener('resize', updateSticky)
+    const observer = new ResizeObserver(updateSticky)
+    observer.observe(content)
+    if (sider instanceof HTMLElement) observer.observe(sider)
     onScroll()
+    updateSticky()
 
     return () => {
       body.removeEventListener('scroll', onScroll)
+      body.removeEventListener('scroll', updateSticky)
+      window.removeEventListener('resize', updateSticky)
+      observer.disconnect()
       body.id = ''
       body.style.overflowY = ''
       body.style.overflowX = ''
@@ -235,6 +254,8 @@ export default function AppNext() {
       if (sider instanceof HTMLElement) {
         sider.style.overflow = ''
         sider.style.height = ''
+        sider.style.alignSelf = ''
+        sider.style.transform = ''
       }
     }
   }, [])
@@ -606,7 +627,7 @@ export default function AppNext() {
           />
         }
         sider={
-          <div className="sidebar">
+          <div className="sidebar sidebar-home">
             {site.sidebar.show_profile !== false && <ProfileCard profile={site.profile} />}
             {site.sidebar.show_service !== false && (
               <ServicePanel