Subscriber to server

[FrancescAlted]

Most of the references to the previous publish-subscriber are gone now, and replaced by client-server paradigm. We still need to decide what to do with the independent-services.md tutorial.

[Copilot]

Pull Request Overview

This PR renames terminology throughout the codebase, replacing "subscriber" with "server" and "publisher" with "client" to reflect a client-server paradigm instead of the previous publish-subscribe architecture.

• Updated references from "subscriber" to "server" in comments, documentation, and configuration files
• Changed "publisher" references to "client" throughout documentation and specifications
• Maintained code functionality while updating terminology for clarity

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pyproject.toml	Updated comment about HDF5 support from "publisher" to "client"
examples/query_server.py	Changed comments referencing "subscriber" to "server"
doc/tutorials/launching-services.md	Updated tutorial text replacing broker/publisher/subscriber with client/server terminology
doc/tutorials/independent-services.md	Removed broker references and updated publisher/subscriber to client/server
doc/tutorials/configuration.md	Updated configuration examples from "subscriber" to "server"
doc/tutorials/cli.md	Changed references from "subscriber" to "server" in CLI documentation
caterva2/tests/services.py	Updated module docstring from "subscriber" to "server"
caterva2/services/settings.py	Changed configuration comment from "subscriber" to "server"
caterva2/clients/cli.py	Updated help text from "subscriber" to "server"
caterva2/client.py	Updated docstrings and comments replacing "subscriber" with "server"
caterva2.sample.toml	Updated configuration comments from "subscriber" to "server"
SPECS.md	Major documentation update replacing publish-subscribe with client-server terminology
README.md	Updated installation and usage instructions with new terminology
README-DEVELOPERS.md	Changed reference from "subscriber" to "server"

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[jdavid]

LGTM