Add "Always show proxy button" to experimental setting

[yueneiqi]

Close #29766

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This PR was primarily authored with Codex using GPT-5-Codex and then hand-reviewed by me. I AM responsible for every change made in this PR. I aimed to keep it aligned with our goals, though I may have missed minor issues. Please flag anything that feels off, I'll fix it quickly.

[23rd]

First of all, the project doesn't build and has errors.
Secondly, it doesn't work very well in some cases. During different account switches and when toggling the proxy itself on/off, the icon still disappears despite enabling this new experimental feature.

[ilya-fedin]

Reading the linked issue

Sometimes, when Telegram cannot connect at all, this button does not appear either, which makes it impossible to quickly access proxy settings.

It sounds like a new option isn't needed at all, just the bug when Telegram can't connect has to be fixed as the icon is supposed to be shown when connecting even if a proxy isn't set

[yueneiqi]

First of all, the project doesn't build and has errors. Secondly, it doesn't work very well in some cases. During different account switches and when toggling the proxy itself on/off, the icon still disappears despite enabling this new experimental feature.

Sorry about that. My initial test was just on my local Windows setup, and it seemed fine(actually not). I've now run it on a fresh 64-bit Windows build and WSL.

Win64:

WSL:

[yueneiqi]

Reading the linked issue

Sometimes, when Telegram cannot connect at all, this button does not appear either, which makes it impossible to quickly access proxy settings.

It sounds like a new option isn't needed at all, just the bug when Telegram can't connect has to be fixed as the icon is supposed to be shown when connecting even if a proxy isn't set

You're right that this option doesn't resolve the issue entirely. However, it does provide users with a helpful shortcut to their proxy settings.

Regarding the bug, I haven't been able to reproduce it on my end. My hope is that this shortcut will give users better context, enabling them to provide a more detailed report if they encounter it again. I will be sure to update this issue (or PR) if I find a way to reproduce or fix it.