- Add heartbeat events to /global/event and /event SSE endpoints
- Send server.heartbeat event every 30s to prevent WKWebView 60s timeout
- Fixes desktop app disconnecting from global events after 1 minute
Changes shell spawn flags from -l to -il so that ~/.zshrc and
~/.bashrc are sourced when starting the desktop app on macOS
and Linux. This fixes missing PATH and other environment
variables that users expect to be available.