Nice, this is exactly what I use for the multi-objective optimizer on a quantum network simulator I'm building — scoring topologies on fidelity/latency/success rate tradeoffs.
Not browser but Electron. For the browser you would have to run a local nodejs server and point the browser app to use the local API. I use electron with nodejs and react for UI. Yes I can switch models.
1. Offline AI file manager
2. Health tracker, sport, food, mental health (CBT) with AI - only for myself, for now(probably forever :)).
3. Community app where you can find people working on the same hobby/idea. I was trying to find someone to work on my small roach size swarm bots, but didn't know how to find same-minded people.