feat: Add SOCKS5 proxy support

[scrense-hash]

Summary

This PR adds full SOCKS5 proxy support to Session Desktop, enabling all application traffic (including onion requests) to be routed through a SOCKS5 proxy server.

Features

• ✅ SOCKS5 proxy with authentication - Username/password support
• ✅ TLS/SSL preservation - Certificate validation and pinning work through proxy
• ✅ Timeout handling - Adjusted timeouts (30s for proxy vs 5s/10s direct)
• ✅ Agent caching - Performance optimization
• ✅ Settings UI - User-friendly proxy configuration page
• ✅ Security - Auto-updater disabled when proxy enabled (prevents traffic leaks)

Changes

18 files changed, 734 insertions(+), 20 deletions(-)

Core Implementation

• InsecureNodeFetch.ts (+195 lines) - SocksProxyAgentWithTls class and integration
• ProxySettingsPage.tsx (+199 lines) - UI for proxy configuration
• settings-key.ts (+15 lines) - Proxy settings storage keys

Integration

• SeedNodeAPI.ts - 30s timeout when proxy enabled
• onionPath.ts - 30s timeout when proxy enabled
• updater.ts - Disable auto-update with proxy (prevents leaks)
• main_node.ts - Electron proxy configuration

Dependencies

• Added: socks@^2.8.3, socks-proxy-agent@^8.0.4

Localization

• English and Russian translations for proxy UI

Security

• TLS settings preserved from original sslAgent
• Certificate pinning works through proxy
• Auto-updater disabled when proxy active (prevents bypass)
• No security regression for production nodes

Testing

✅ Built and tested on:

• Linux (deb, rpm, AppImage, freebsd)
• Windows x64
• macOS (arm64, x64)

Use Cases

• Bypass network restrictions and DPI
• Route all Session traffic through Tor/I2P
• Corporate/institutional network access
• Enhanced privacy configuration

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🤖 Generated with Claude Code

[scrense-hash]

Working Build Available

Tested build artifacts with full SOCKS5 proxy UI are available here:
https://github.com/scrense-hash/session-desktop/actions/runs/20663400559#artifacts

What's included:

These commits add critical fixes on top of the main SOCKS5 proxy support:

• Fix proxy agent TLS caching - Proper caching of SOCKS proxy agents with TLS options to avoid connection issues
• Fix TLS options flag - Correct handling of TLS configuration in proxy agent initialization
• Guard job runner logging - Prevent crashes when window object is undefined in main process context
• Guard window access in focusListener - Fix ReferenceError: window is not defined error at startup

Testing status:

✅ Tested on Linux (AppImage, deb)
✅ Proxy settings UI displays correctly in Settings menu
✅ Client successfully connects through SOCKS5 proxy
✅ No crashes in main process
✅ All artifacts include the complete proxy configuration interface

Download the AppImage or deb package from the artifacts link above to test the full functionality.