documentation: Add manuel for mitigating tunnelvision attacks

docs/manual/misc/tunnelvision.md

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+---
+icon: material/book-lock-open
+---
+
+# TunnelVision
+
+TunnelVision is an attack that uses DHCP option 121 to set higher priority routes
+so that traffic does not go through the VPN.
+
+Reference: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-3661
+
+## Status
+
+### Android
+
+Android does not handle DHCP option 121 and is not affected.
+
+### Apple platforms
+
+Update [sing-box graphical client](/clients/apple/#download) to `1.9.0-rc.16` or newer,
+then enable `includeAllNetworks` in `Settings` — `Packet Tunnel` and you will be unaffected.
+
+Note: when `includeAllNetworks` is enabled, the default TUN stack is changed to `gvisor`,
+and the `system` and `mixed` stacks are not available.
+
+### Linux
+
+Update sing-box to `1.9.0-rc.16` or newer, rules generated by `auto-route` are unaffected.
+
+### Windows
+
+No solution yet.
+
+## Workarounds
+
+* Don't connect to untrusted networks
+* Relay untrusted network through another device
+* Just ignore it