Add support for publisher field

[andrius-puksta-sensmetry]

All the basics are done:

• serializing and deserializing .project.json, field is optional
• creating/reading lockfile, field is optional, will be included if present
• sysand info get/set/clear
• sysand init (required arg in core, optional in CLI)
• bindings (required arg for init)
• basic docs

Currently publisher has no effect on anything.

Currently not all tests are updated.

[consideRatio]

You can install prek (Rust variant of the old-school pre-commit CLI), and then install git hooks that trigger before commits, reformatting things before a git commit goes through, allowing you to avoid getting fixes pushed.

Format and lint all other code based on configuration in
`.pre-commit-config.yaml`, either with prek or pre-commit, available to install
via uv or pip.

```sh
prek run -a

# like this, you ensure this formatting is run before git commits are made
prek install
```