feature: Reducing the downtime of a long-running process

Hi, I work on a web application written in Rust.
I use bacon as a watcher to restart automatically the backend server whenever I make a change. Here’s my current `bacon.toml` file:

```toml
default_job = "check"

[jobs.check]
command = ["cargo", "check"]
need_stdout = false

[jobs.run]
command = [
"cargo", "run", "server"
]
need_stdout = true
allow_warnings = true
background = false
on_change_strategy = "kill_then_restart"
watch = ["templates/"]
```

Compiling my project takes about 5s. When I edit an HTML file in the `templates` directory (these files are embedded in the rust binary using [askama](https://askama.readthedocs.io/en/stable/)) and save it, `bacon` triggers a rebuild and restart. The process looks like this:

I’d like to reduce the downtime of my Rust binary during this process. Ideally, it would work more [like this](https://excalidraw.com/#json=WLHl4Y6abXyxRmkPhsMZ9,mGweupzet9ZJjdVRV38HRw):

I tried using the `wait_and_restart` strategy, but the server never restarts. I’m not very familiar with bacon, so I might be missing something in the configuration.

Any help would be appreciated!
Thanks in advance.

Start with the bacon.toml configuration and compare the current kill_then_restart behavior with the attempted wait_and_restart strategy. Reproduce the workflow using the templates/ watch path and cargo run server command, then trace how the process lifecycle is handled. Done means template changes trigger a restart with less downtime and the server does not remain stopped.

Written by the indexing model from the issue text.