Update README.md with current stage of the project

[Max-V-Seltz]

Hello everybody!
Huge thanks for the amazing progress throughout 2025.

As we kick off 2026, does it make sense to update README.md to show all the progress you've made?

Specifically, this section:

### Planned Changes from Upstream

This is a list of things that Zedless will do differently.

- No reliance on proprietary cloud services
  - Components and features that strictly rely on non-selfhostable cloud services will be removed.
- No spyware
  - Telemetry and automatic crash reporting will be removed.
- Priority on bringing your own infrastructure
  - Any feature that makes use of a network service will allow you to configure which provider to use in a standard format, e.g. by specifying the base URL of an API.
  - Any such feature will not have a list of "default providers".
  - Any such feature will be disabled by default.
- No CLA
  - Contributors' copyright shall not be reassigned.
  - No rugpulls.

P.S. One way to update the section is to link a tracking issue for each bullet point in the list.
I'm happy to help with PR if someone involved in the development could support me with the required information.

Happy New Year to everyone!
Max V