chore: add Flue deploy workflow on merge to production - #32772

Fix the following review findings in PR #32772 (https://github.com/cloudflare/cloudflare-docs/pull/32772).

Before making changes, review each finding and present a brief summary table:
- For each finding, state whether you agree, disagree, or need clarification
- If you disagree (e.g. the fix requires disproportionate effort for minimal benefit,
  or the finding is factually incorrect), explain why
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After triaging, follow this order:
1. Post a comment on this PR for any findings you are skipping, with the finding ID and your reasoning.
2. Then commit the fixes for the legitimate findings.

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push triggers a review, so skip comments posted after the push will be missed.

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## Code Review

### Warnings (1)

#### CR-96720a31e5da · Incorrect Google Chat notification format
- **File:** `.github/workflows/flue-deploy.yml` line 54
- **Issue:** The message uses Slack-style `<https://...|View run>` and `\n` inside bash double quotes. Google Chat's text field uses `[text](url)` for links, and in this quoting the `\n` remains a literal backslash-n rather than a newline.
- **Fix:** Format the message as Google Chat Markdown with `[View run](https://github.com/$REPO/actions/runs/$RUN_ID)` and use `$'...'` or real newlines so newlines render correctly.