feat: UX improvements — secure webhooks, locale fixes, dynamic languages, UI polish

- Remove top paginator from dashboard events, keep only bottom
- Fix test message locale: pass UI locale to email/matrix bot tests
- Convert webhook auth mode from text input to icon grid selector
- Generate secure UUID tokens for webhook URLs instead of sequential IDs
- Move Recent Payloads into per-provider expandable container (lazy-loaded)
- Make template config languages dynamic via app settings instead of hardcoded
- Change default dev port to 5175

frontend/src/lib/grid-items.ts

@@ -58,6 +58,14 @@ export const memorySourceItems = (): GridItem[] => [
 	{ value: 'native', icon: 'mdiMemory', label: t('trackingConfig.memorySourceNative'), desc: t('gridDesc.memorySourceNative') },
 ];
 
+// --- Webhook auth mode ---
+
+export const webhookAuthModeItems = (): GridItem[] => [
+	{ value: 'none', icon: 'mdiLockOpen', label: t('providers.authNone'), desc: t('gridDesc.authNone') },
+	{ value: 'bearer_token', icon: 'mdiKey', label: t('providers.authBearer'), desc: t('gridDesc.authBearer') },
+	{ value: 'hmac_sha256', icon: 'mdiShieldKey', label: t('providers.authHmac'), desc: t('gridDesc.authHmac') },
+];
+
 // --- Locale ---
 
 export const localeItems = (): GridItem[] => [