Align branch naming guidelines with GitHub issue-based branch defaults

[lex57ukr]

Goal

Align the project’s branch naming guidelines with GitHub’s default branch naming when creating branches directly from issues.

Scope

• Document GitHub’s default issue-based branch naming pattern:
  <issue-number>-<issue-title-slug>
• Update contributor guidelines to recommend using GitHub-generated branch names when branching from issues
• Deprecate the previously used issue-NN- prefix in favor of the default pattern
• Ensure examples in documentation reflect the updated convention

Outcome

• Branch naming is consistent with GitHub’s tooling
• No manual renaming or workaround is required
• Contributors can rely on GitHub UI defaults without ambiguity

Notes

• Branch naming is not configurable at the repository or organization level in GitHub
• This change is a documentation and convention update only

[lex57ukr]

Triage

This is a documentation-only change.

Recommended action:

• Update CONTRIBUTING.md to reflect GitHub’s default issue-based branch naming
• Prefer GitHub-generated branch names over custom prefixes

[lex57ukr]

Completed via PR #27. Branch naming guidelines are aligned with GitHub issue based branch defaults.