fix: instant widget lead assignment + SSE notification

Widget leads were invisible to agents for up to 90s (60s auto-assign
poll + 30s worklist poll). Now triggers immediate auto-assign after
lead creation and emits SSE worklistUpdate so agents see new widget
leads and appointments instantly.

Also excluded packages/ from tsconfig build to prevent widget source
compilation errors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tsconfig.build.json

@@ -1,4 +1,4 @@
 {
   "extends": "./tsconfig.json",
-  "exclude": ["node_modules", "test", "dist", "widget-src", "public", "data", "**/*spec.ts"]
+  "exclude": ["node_modules", "test", "dist", "widget-src", "packages", "public", "data", "**/*spec.ts"]
 }