Feature/workspaces cli

[VictorMorand]

Add workspaces list CLI Command

Description

This PR introduces a new CLI command group to easily inspect and manage experimaestro workspaces configured in the global ~/.config/experimaestro/settings.yaml. There was no quick way to view them from the terminal.
The new experimaestro workspaces list command outputs all registered workspaces, their local paths, and their remote
status. It includes a --verbose (-v) flag that cleanly dumps the internal properties for each workspace (such
as env variables, ssh parameters, history limits, and auxiliary folders) using a formatted YAML layout.

Changes Included

• New CLI Module: Added src/experimaestro/cli/workspaces.py containing the new workspaces group and list subcommand.
• CLI Registration: Imported and attached the workspaces group to the root CLI context in src/experimaestro/cli/init.
py.
• Documentation: Updated docs/source/cli.md with a new Workspaces Management section documenting the command and its
verbose flag.

Example Usage

Standard Output:

$ experimaestro workspaces list
splade-gpu: /data/user/splade [remote: user@gpu]
mice-jz: /path/to/micev2 [remote: user@JZ]
debug: /Users/home/experiments/debug

Verbose Output:

$ experimaestro workspaces list -v
splade-gpu: /data/user/splade [remote: user@gpu]
env: {}
alt_workspaces: []
folders: []
max_retries: 3
triggers: []
history:
  max_done: 5
  max_failed: 1
ssh:
  host: user@gpu
  shell_init: null
  uv_offline: false
...
```