feat: add official pre-commit hook support

[juftin]

Summary

Closes #2562.

Adds official pre-commit support by adding a .pre-commit-hooks.yaml at the repository root. This allows users to reference repo: https://github.com/go-task/task directly in their .pre-commit-config.yaml rather than maintaining a local hook definition.

Changes

• .pre-commit-hooks.yaml: defines a single task hook with language: golang, pass_filenames: false, require_serial: true, and minimum_pre_commit_version: "3.0.0" (required for golang language support)
• precommit_test.go: validates the hook file is present, parses as valid YAML, and asserts all fields are correctly set
• website/src/docs/integrations.md: documents the integration with setup instructions, a configuration reference table, and collapsible examples covering common use cases
• website/src/docs/changelog.md: adds a changelog entry