Verify edge cases from official WireGuard macOS app issues

[korjwl1]

Context

Based on the analysis in docs/wireguard-macos-issues-analysis.md, most issues with the official WireGuard macOS app are resolved in WireGuide (latest wireguard-go, no NetworkExtension dependency, kill switch implemented). However, some edge cases need verification.

Items to Verify

Config persistence across macOS updates

• Official app had configs wiped on Tahoe 26.1 → 26.2 update
• WireGuide stores configs in its own app data, likely safe — but needs real-world testing across a macOS update cycle

MTU handling

• Multiple Reddit reports of connections fixed by lowering MTU to 1280
• This is a network environment issue, not client-specific — but could improve UX by surfacing MTU diagnostics or offering easy MTU adjustment

Traffic leak with AllowedIPs = 0.0.0.0/0

• Official app had no kill switch; WireGuide has one
• Need to verify kill switch covers all edge cases (sleep/wake, network switch, sudden disconnect)

DNS stability on macOS Tahoe

• WireGuide uses networksetup-based DNS configuration
• Verify this approach is stable on Tahoe 26.x, especially across sleep/wake and network changes

Reference

• Analysis document
• Reddit reports: https://www.reddit.com/r/WireGuard/comments/1oto85i/, https://www.reddit.com/r/WireGuard/comments/1q8xi8h/, https://www.reddit.com/r/WireGuard/comments/1fzvrvc/