Docs: CI usage example with JSON reports

[guohuancui123-a11y]

Goal

Add a small CI example showing how RepairLoop can be used as an automation primitive.

Why

RepairLoop is useful in terminals, but JSON reports make it especially interesting for CI and agent workflows. A simple example would help users understand how to integrate it safely.

Proposed content

• A minimal GitHub Actions example.
• A command using repair-loop repair --json-report -- <command>.
• A short explanation of preview mode vs --apply.
• A warning that CI auto-apply should be used only in trusted, controlled repositories.

Acceptance criteria

• Add a docs page or README section with the CI example.
• Example command is copy-pasteable.
• The example keeps dry-run as the default.
• Link the example from README.

Safety notes

Do not encourage blind auto-committing of generated repairs. CI usage should emphasize inspection and controlled apply behavior.