chore: upgrade TypeScript to 6.0.3 and modernize tsconfig

- typescript 5.9.3 to 6.0.3
- moduleResolution Node to bundler (correct for Vite projects)
- target/lib ES2016 to ES2020 (enables flatMap, Promise.allSettled)
- Fix global to globalThis in initMatrix.ts (browser env)
- Fix EventEmitter default to named import in CallControl.ts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -162,7 +162,7 @@
     "lint-staged": "17.0.5",
     "prettier": "3.8.3",
     "semantic-release": "25.0.3",
-    "typescript": "5.9.3",
+    "typescript": "6.0.3",
     "vite": "6.4.2",
     "vite-plugin-pwa": "1.3.0",
     "vite-plugin-static-copy": "4.1.0"