Update AUTH_METHODS_TELEGRAM.md

[PentiumB]

Обновление справки под новый OAuth2

[greptile-apps]

Greptile Summary

This PR updates the Telegram authentication help article (AUTH_METHODS_TELEGRAM.md) to reflect the new OAuth2 / OpenID Connect flow introduced by Telegram for BotFather, replacing the older "Set Domain" approach with a proper Client ID / Client Secret setup and a redirect URI configuration.

Key changes:

• Replaces the old "Set Domain" steps with the new OpenID Connect Login setup flow via BotFather MiniApp
• Updates the "Настройка доступа" section to reference Client ID, Client Secret, and Frontend Domain instead of just a bot token
• Adds a new known-issues note about reverse proxy (cookie-based protection) compatibility with the /oauth2/ path

Issue identified:

• The step list in "Настройка бота" skips step 6 — it jumps from step 5 directly to step 7 — which will confuse users following the guide sequentially. The fix is to renumber step 7 to step 6.

Confidence Score: 3/5

• Safe to merge after fixing the step numbering gap in the setup guide
• The PR contains accurate documentation updates reflecting the new Telegram OAuth2 flow. The only issue is a concrete numbering gap in the setup guide (steps 5→7, missing 6) that will confuse users but does not cause technical harm. This single, straightforward fix is required before merge.
• _panel-docs/help-articles/ru/AUTH_METHODS_TELEGRAM.md — fix step numbering (step 7 should be step 6)

Sequence Diagram

sequenceDiagram
    actor User
    participant BotFather
    participant Panel as Remnawave Panel
    participant Telegram as Telegram OAuth2

    User->>BotFather: Open MiniApp → Select Bot → Bot Settings
    User->>BotFather: Delete existing Web Login domain
    User->>BotFather: Switch to OpenID Connect Login
    BotFather-->>User: Provides Client ID & Client Secret
    User->>BotFather: Add Allowed URL (Trusted Origin + Redirect URI)
    User->>Panel: Configure Client ID, Client Secret, Frontend Domain
    User->>Panel: Open login page
    Panel->>Telegram: Redirect to Telegram OAuth2
    Telegram-->>User: Prompt Telegram login
    User->>Telegram: Authenticate
    Telegram->>Panel: Redirect to /oauth2/callback/telegram
    Panel-->>User: Authenticated session

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_{Last reviewed commit: 0c1c4d2}

[greptile-apps]

The numbered list skips step 6 — it jumps from step 5 (line 15) directly to step 7 here. This will confuse users following the setup guide sequentially. Update the numbering to be consecutive:

Suggested change

	7. Нажмите Add an Allowed URL.
	Укажите следующие значения:
	- Trusted Origins: https://panel.domain.com
	- Redirect URIs: https://panel.domain.com/oauth2/callback/telegram
	6. Нажмите Add an Allowed URL.
	Укажите следующие значения:
	- Trusted Origins: https://panel.domain.com
	- Redirect URIs: https://panel.domain.com/oauth2/callback/telegram