feat: 路由模式重构(full/proxy/bypass) + CIDR动态URL获取 + 命中统计 + 连接稳定性修复

路由模式与CIDR配置重构:
- 路由模式从 full/split/custom 改为 full/proxy/bypass，移除 split 和 custom
- CIDR 按 IPv4/IPv6 分开配置，支持静态 CIDR + URL 动态获取
- URL 支持"代理前获取"(直连)和"代理后获取"(走隧道)两种时机
- 数据库迁移 v5 自动转换旧数据(custom_cidrs 拆分为 cidr_v4/v6，custom->proxy，split->full)

CIDR命中统计:
- 状态栏显示当前路由模式及 IPv4/IPv6 CIDR 命中数
- 代理模式: 显示命中/总数; 绕过模式: 显示已配置数 + 未命中目的地址数
- cidrTracker 在 pumpPackets 中逐包检查出站目的IP

连接稳定性修复(多轮):
- transport.Connect 添加 ctx 监听 goroutine，取消时关闭WS中断阻塞的ReadMessage
- auth.Login 加 context.Context 参数，可被 cancel 中断
- Disconnect() 先删路由再关TUN，避免断网窗口
- startSession 在 Connect 前释放 d.mu，避免锁持有过久
- onConnect 移除 SendStop 消除竞态
- before-proxy CIDR 获取移到 run 循环前，并行获取+5s超时，重连复用
- cidrTracker 加 RWMutex 防数据竞争

UI修复:
- CIDR URL 输入框改为水平滚动+纵向布局，防止撑宽窗口
- 路由模式为full时隐藏CIDR配置区域

internal/i18n/en.toml

@@ -37,6 +37,12 @@ TxV6Zero = "↑ 0 B  0 bps"
 RxTotalZero = "Total ↓ 0 B  0 bps"
 TxTotalZero = "↑ 0 B  0 bps"
 
+StatusRoutingMode = "Routing Mode: {{.mode}}"
+CIDRHit = "hit"
+CIDRConfigured = "configured"
+CIDRUnmatched = "unmatched"
+CIDRDestinations = "destinations"
+
 DlgNoProfileTitle = "No Profile"
 DlgNoProfileEditMsg = "Select a profile to edit."
 DlgNoProfileConnectMsg = "Please select or create a profile first."
@@ -88,10 +94,15 @@ FieldUsername = "Username"
 FieldPassword = "Password"
 FieldAuthMode = "Auth Mode"
 FieldRoutingMode = "Routing Mode"
-FieldCustomCIDRs = "Custom CIDRs (comma-separated)"
+FieldCIDRV4 = "IPv4 CIDRs (comma-separated)"
+FieldCIDRV6 = "IPv6 CIDRs (comma-separated)"
+FieldCIDRV4URLs = "IPv4 CIDR URL Sources"
+FieldCIDRV6URLs = "IPv6 CIDR URL Sources"
 FieldMTUOverride = "MTU Override"
 
-PlaceholderCIDRs = "10.0.0.0/8, 172.16.0.0/12"
+PlaceholderCIDRV4 = "10.0.0.0/8, 172.16.0.0/12"
+PlaceholderCIDRV6 = "fd00::/8, 2001:db8::/32"
+PlaceholderCIDRURL = "https://example.com/cidrs.txt"
 PlaceholderMTU = "0 = use server MTU"
 PlaceholderPasswordUnchanged = "(unchanged)"
 PlaceholderServerIPs = "IPv4/IPv6 supported, e.g. 1.2.3.4, 5.6.7.8"
@@ -101,8 +112,14 @@ AuthModeJWT = "JWT"
 AuthModePassword = "Password"
 
 RoutingModeFull = "Full Tunnel"
-RoutingModeSplit = "Split Tunnel"
-RoutingModeCustom = "Custom"
+RoutingModeProxy = "Proxy CIDR"
+RoutingModeBypass = "Bypass CIDR"
+
+FetchTimingBefore = "Before Proxy"
+FetchTimingAfter = "After Proxy"
+
+BtnAddURL = "Add URL"
+BtnRemoveURL = "Remove"
 
 FieldTLS = "TLS Certificate"
 FieldTLSCACert = "CA Certificate (PEM)"