Log runner details at the start of each job

[ColinKinloch]

This prints a header containing runner details to the gitlab log at the start of each job.

The format of the header is:

Running with demo-runner 0.3.2 (7fd27f7-dirty)
  on gitlab-runner-rs test runner XPgS3LCJG, systemd ID: s_82de14b38222

I attempted to match the string printed by the original gitlab-runner:

• Build.printRunningWithHeader()
  • AppVersionInfo.Line()
  • RunnerCredentials.ShortDescription()
    • helpers.ShortenToken()

Fixes: collabora/lava-gitlab-runner#18

[Copilot]

Pull request overview

This PR adds a “runner details” header to the GitLab trace output at the start of each job, aiming to match the upstream gitlab-runner header format (runner version line + “on …, systemd ID …” line).

Changes:

• Emit a runner header at the beginning of job execution (job.output_runner_header()), including app version info and a shortened runner token.
• Update integration/unit tests to tolerate the new header prefix and validate expected header content.
• Add token-shortening logic (with regex) and adjust the mock runner token to include a glrt- prefix.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
gitlab-runner/src/run.rs	Calls output_runner_header() at the start of each job run.
gitlab-runner/src/job.rs	Implements output_runner_header() formatting and output.
gitlab-runner/src/client.rs	Adds app version formatting and runner-token shortening logic.
gitlab-runner/tests/integration.rs	Updates job log assertions to account for the new header.
gitlab-runner/tests/runhandler.rs	Loosens log assertions to allow additional header content.
gitlab-runner/Cargo.toml	Adds regex dependency.
gitlab-runner-mock/src/lib.rs	Updates mock runner token prefix to match expected shortening logic.
Cargo.lock	Locks regex dependency updates.

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[ColinKinloch]

Re the LLM review:

I accidentally left the .to_owned() and .as_ref() in while comparing the outputs of Regex::split and Regex::replace_all, I'm surprised clippy didn't complain.
It does compile though, In this case Option<T>::to_owned() seems to be using blanket implementation which calls .clone() on T which in this case is the blanket implementation for &T, cloning the reference. So it sidesteps the &str implementation of .to_owned().

On replacing using std::str::from_utf8 instead of str::from_utf8, the documentation says the std one is an alias to the primitive one so there's no reason to change it.

The error string was introduced in 7f8d2da and appears to be a typo from copy pasting. I've opened a separate MR for that: #136