fix: Linux AppImage Wayland EGL startup

[hhungxun]

Summary

• Re-exec Linux AppImage launches on Wayland with the first available system libwayland-client.so in LD_PRELOAD when the user has not already set a preload.
• Preserve existing AppImage WebKitGTK startup safeguards and explicit user environment overrides.
• Document the EGL startup failure and manual workaround for AppImage users.

Root Cause

On some GNOME Wayland systems, the AppImage can load Wayland/EGL-related libraries in an order that prevents GTK/WebKit from creating the default EGL display. The reported workaround was to preload the system Wayland client library before launching Tolaria.

Validation

• cargo fmt --manifest-path src-tauri/Cargo.toml --check
• cargo test --manifest-path src-tauri/Cargo.toml linux_appimage
• cargo clippy --manifest-path src-tauri/Cargo.toml --tests -- -D warnings
• pnpm lint
• npx tsc --noEmit
• pnpm exec vitest run src/App.test.tsx --silent
• full pre-commit hook with VITEST_MAX_WORKERS=1: 283 files, 3354 tests passed