refactor: deprecate Security Center, move content to Threat Intellige…

[alexmoraru7]

…nce & Application Security

RFC: Deprecate Security Center documentation section

• Move infrastructure/ → application-security/infrastructure/
• Move investigate/ → threat-intelligence/investigate-portal/
• Move brand-protection → threat-intelligence/brand-protection
• Move indicator-feeds → threat-intelligence/custom-indicator-feeds
• Move intel-apis/ → threat-intelligence/threat-intelligence-apis/
• Move cloudforce-one/ → threat-intelligence/threat-intelligence-platform/
• Move changelog, get-started → threat-intelligence/
• Rewrite threat-intelligence/index.mdx as new overview page
• Update all frontmatter product references and internal links
• Add 301 redirect rules for every moved page + catch-all
• Delete old security-center/ directory

Summary

Screenshots (optional)

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The change adheres to the documentation style guide.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.

[cloudflare-docs-bot]

Review

❌ Review failed for commit 64a24a3. This is usually a transient error — it will retry on the next push.