Adds standardised mise tasks for Go projects gated on golang:
- test, test:unit, test:integration, test:coverage, lint, format

Part of https://gitlab.com/groups/gitlab-org/quality/-/work_items/357

Add `test:contract` task to `.mise.toml.jinja` so developers can run
Go contract tests locally with `mise run test:contract`. Gated on
the `golang` copier variable alongside the other Go tasks.

Part of gitlab-org/quality/quality-engineering/team-tasks#4480

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

chore(deps): update dependency gitlab-org/caproni to v2.50.0

See merge request !736

chore(deps): update dependency gitlab-org/caproni to v2.50.2

See merge request !738

chore(deps): update dependency gitlab-com/gl-infra/platform/runway/fairway to v1.27.0

See merge request !740

chore(deps): update common-ci-tasks to v4.16

See merge request !739

feat(golang): add contract test mise task

See merge request !673