chore(ci): add job timeouts to modelina-specific GitHub Actions workflows

[mr-raj12]

Context

Jobs in workflows that are maintained in this repository (not copied from asyncapi/.github) do not set timeout-minutes. When a step hangs, the run can keep consuming runner minutes until the platform default limit.

Proposal

Add an explicit timeout-minutes on each job, using conservative values: shorter limits for coverage, runtime language smoke jobs, and release helper workflows; higher limits where work is heavier (for example multi-arch Docker builds and website plus Lighthouse steps).

Scope

Only workflow files without the centrally managed banner at the top of the file.

Additional notes

A pull request will implement this without changing centrally managed workflows, so future ci: update of files from global .github repo syncs are unaffected.

[github-actions]

Welcome to AsyncAPI. Thanks a lot for reporting your first issue. Please check out our contributors guide and the instructions about a basic recommended setup useful for opening a pull request.
Keep in mind there are also other channels you can use to interact with AsyncAPI community. For more details check out this issue.