[Feature]: Add concurrency cancellation and job timeouts to the workflows

[rogkne]

Feature Description

Give the workflows a concurrency group that cancels superseded runs and a timeout on
each job so a stuck step cannot run for hours.

Use Case

Neither workflow sets a concurrency group, so pushing several times to a pull request
or to main leaves redundant full runs queued and running. No job sets timeout-minutes,
so a hung network step or a stuck build can occupy a runner for the default six hours,
which wastes minutes and delays feedback.

Proposed Solution

Add a concurrency group keyed on the workflow and the ref with cancel in progress
enabled for pull requests, and set a sensible timeout-minutes on each job. Leave the
release and publish jobs without cancellation so a tag build is never interrupted.

Additional Context

• .github/workflows/pull-request.yml and .github/workflows/build.yml
• The publish-doc job already uses a pages concurrency group that should stay as is