feat(ui): redesign the overview page as a trend-first command deck

Replace the ten-small-cards overview with an action bar, four vitals
tiles carrying 72-sample sparklines seeded from /server/history, a
two-series throughput chart, a TCP/UDP connections chart, and a
grouped system strip (uptime xray|os, panel ram|threads, ip
addresses). StatusCard and XrayStatusCard are deleted; every modal
stays reachable from the action bar, the Xray error message moves
into a tooltip on the state pill, and the panel version text keeps
opening the update modal (the dev-channel switch lives there) even
when no update is available. Live values sit beside the
upload/download and tcp/udp legends, a health sentence appears only
when a vital crosses the shared warn/crit thresholds now exported
from models/status, and load average is left to System History.

The sidebar becomes an auto-collapsed 72px icon rail that expands as
an overlay on hover: rail width, brand-row height and menu paddings
are pinned so nothing shifts during the transition, the collapsed-menu
tooltips are disabled, hover state survives the per-page sidebar
remounts (with a matches(':hover') resync), and the manual collapse
trigger is gone.

Sparkline gains rgb()/rgba() support in its fill gradient, a
showLegend prop so pages stop reaching into its internals, and loses
a dependency-less repaint effect that doubled canvas paints. Chart
tooltips show clock time via the new TimeFormatter.formatClock;
accents come from theme tokens instead of status.cpu.color. Verified
by screenshot at 390/800/1150/1280/1400/1600px in light and dark,
en and fa-IR, plus programmatic geometry checks on the sidebar.
Locale files gain 8 keys and lose 9 dead ones across all 13
languages.

internal/web/translation/zh-CN.json

@@ -106,7 +106,6 @@
     "routing": "路由",
     "outbounds": "出站",
     "apiDocs": "API 文档",
-    "link": "管理",
     "donate": "捐赠",
     "hosts": "主机",
     "docs": "文档",
@@ -127,12 +126,9 @@
     },
     "index": {
       "cpu": "CPU",
-      "logicalProcessors": "逻辑处理器",
-      "frequency": "频率",
       "swap": "交换空间",
       "storage": "存储",
       "memory": "内存",
-      "threads": "线程",
       "xrayStatus": "Xray",
       "stopXray": "停止",
       "restartXray": "重启",
@@ -153,7 +149,6 @@
       "xrayStatusRunning": "运行中",
       "xrayStatusStop": "停止",
       "xrayStatusError": "错误",
-      "operationHours": "系统正常运行时间",
       "systemHistoryTitle": "系统历史",
       "historyTitleCpu": "CPU 使用率",
       "historyTitleMem": "内存使用率",
@@ -171,7 +166,6 @@
       "historyTabLoad": "负载",
       "historyTabConnections": "连接数",
       "historyTabDiskUsage": "磁盘使用量",
-      "charts": "图表",
       "xrayMetricsTitle": "Xray 指标",
       "xrayTitleHeap": "已分配的堆内存",
       "xrayTitleSys": "向操作系统保留的内存",
@@ -200,7 +194,6 @@
       "overallSpeed": "整体速度",
       "upload": "上传",
       "download": "下载",
-      "totalData": "总数据",
       "sent": "已发送",
       "received": "已接收",
       "xraySwitchVersionDialog": "您确定要更改 Xray 版本吗？",
@@ -250,7 +243,18 @@
       "exportDatabasePgDesc": "点击将当前数据库的 PostgreSQL 转储（.dump）下载到您的设备。",
       "importDatabasePgDesc": "点击选择并上传 PostgreSQL 备份（.dump）、SQLite 数据库（.db）或 SQLite 迁移导出文件以恢复您的数据库。此操作将替换所有当前数据。",
       "migrationDownload": "下载迁移文件",
-      "migrationDownloadPgDesc": "点击下载由 PostgreSQL 数据构建的 .db SQLite 数据库，可用于在 SQLite 上运行本面板。"
+      "migrationDownloadPgDesc": "点击下载由 PostgreSQL 数据构建的 .db SQLite 数据库，可用于在 SQLite 上运行本面板。",
+      "avg": "均值",
+      "peak": "峰值",
+      "free": "剩余",
+      "openSockets": "打开的套接字",
+      "throughputSub": "网卡总计",
+      "avgWindow": "窗口均值",
+      "healthWarm": "{list} — 偏高",
+      "healthCritical": "{list} — 危险",
+      "panel": "面板",
+      "threads": "线程",
+      "uptime": "运行时间"
     },
     "inbounds": {
       "totalDownUp": "总上传 / 下载",