chore: gate CodeRabbit reviews behind the coderabbit label

[jaysin586]

What

Gates CodeRabbit auto-reviews behind the coderabbit label and stops per-push re-reviews, so simple fast-moving PRs no longer burn the hourly rate limit.

• reviews.auto_review.enabled: false — no automatic review on every PR
• reviews.auto_review.labels: ['coderabbit'] — adding the coderabbit label triggers a review (per CodeRabbit docs, the labels trigger works even when enabled is false)
• reviews.auto_review.auto_incremental_review: false — pushes no longer re-trigger reviews

How to invoke a review now

• Add the coderabbit label to the PR (created in this repo alongside this PR), or
• Comment @coderabbitai review (incremental) / @coderabbitai full review on any PR

🤖 Generated with Claude Code

Note: this repo had no .coderabbit.yaml, so the file is seeded from the org baseline (svelte-markdown) with the label gating applied. The path_instructions / labeling_instructions in the baseline are Svelte-package-oriented — trim if irrelevant here.

@coderabbitai ignore