[BUG] Global Merge ipv6: false is overridden by the Settings IPv6 toggle

问题描述 / Describe the bug

Description

When a profile uses Global Extend Merge to explicitly disable IPv6:

ipv6: false

dns:
  ipv6: false

Clash Verge Rev may still generate a final runtime config with top-level ipv6: true if Settings -> Clash Settings -> IPv6 is enabled.

This is confusing because the Merge editor appears to save the override successfully, but the generated/current config and mihomo runtime state may still use the UI-level IPv6 value. In my case this caused TUN/direct connections to domestic sites to try IPv6 addresses and fail with no route to host.

Observed layering before turning off the app-level IPv6 setting:

Global Extend Merge:        ipv6=false, dns.ipv6=false
Remote profile cache:       ipv6=false
Generated clash-verge.yaml: ipv6=true, dns.ipv6=false
Runtime /configs:           ipv6=true

After turning off Settings -> Clash Settings -> IPv6, the generated config and runtime state became correct:

runtime mode="rule"
runtime ipv6=false
runtime tun.enable=true

Expected behavior

One of these should happen:

1. Explicit profile/Merge config should take priority over the UI IPv6 toggle; or
2. The UI should clearly show that the Settings IPv6 toggle has higher priority and will override Merge; or
3. If the UI setting owns the final value, the Merge editor should warn/block conflicting fields such as top-level ipv6.

Related: #7864 seems to address preserving explicitly disabled DNS IPv6 in TUN mode. This issue is about the top-level app-owned IPv6 setting overriding explicit Merge config.

软件版本 / CVR Version

Clash Verge Rev v2.5.2

复现步骤 / To Reproduce

1. Use a remote profile in rule mode with TUN enabled.
2. Keep Settings -> Clash Settings -> IPv6 enabled.
3. Open the profile's Global Extend Merge editor.
4. Add and save:

ipv6: false

dns:
  ipv6: false

1. Reload/reactivate the profile.
2. Open Current Config or query mihomo /configs.
3. Observe that top-level ipv6 is still generated as true, despite Merge explicitly setting ipv6: false.
4. Turn off Settings -> Clash Settings -> IPv6 and reload. The generated/runtime config then becomes ipv6: false.

操作系统 / OS

• Windows
• Linux
• MacOS

操作系统版本 / OS Version

macOS 26.6.2 (Build 25G83)

日志(勿上传日志文件，请粘贴日志内容) / Log (Do not upload the log file, paste the log content directly)

Relevant sanitized output:


Global Extend Merge:        ipv6=false, dns.ipv6=false
Remote profile cache:       ipv6=false
Generated clash-verge.yaml: ipv6=true, dns.ipv6=false
Runtime /configs:           mode="rule", ipv6=true, tun.enable=true


Example runtime warning before disabling app-level IPv6:


[TCP] dial 国内网站 (match GeoIP/cn) [fdfe:dcba:9876::1]:53295 --> [240e:f7:e010:1108:3::8]:443 error: dial tcp [240e:f7:e010:1108:3::8]:443: connect: no route to host


After disabling Settings -> Clash Settings -> IPv6:


runtime mode="rule"
runtime ipv6=false
runtime tun.enable=true