Summary

• Wrap startWebServer() in try-catch in the main entry point (src/index.ts)
• Log error and exit gracefully with app.exit(1) when port is occupied
• Other callers (webuiBridge, webuiConfig, server.ts) already had error handling

Sentry: ELECTRON-N — 1,933 events

Closes #1732

Verification

• Process: main (Electron app init) — deeply coupled to Electron lifecycle, not unit-testable
• The fix is a defensive try-catch wrapper; all other callers follow the same pattern
• Type check and lint pass

Test plan

• bunx tsc --noEmit passes
• Lint and format clean
• Manual: start two AionUi instances in WebUI mode on same port → second should log error and exit cleanly