- Server: /oidc-callback HTML page exchanges Authentik code for token,
displays it for user to copy into the desktop app's Token tab
- oidc.ts: desktop mode uses apiUrl+/oidc-callback as redirect URI,
encodes PKCE verifier in state parameter
- Config.svelte: add Server URL field to OIDC tab for desktop UX
- Caddy: add /oidc-callback to enroll bypass (no Authentik gate)
- App: favicon.png as system tray icon, window title 'Oikos'
- web/index.html: title 'Oikos'
