Remove legacy `/content/nap-waf` directory to reduce maintenance overhead and improve AI accuracy

[travisamartin]

Problem Statement

The /content/nap-waf directory contains legacy documentation for older NGINX App Protect WAF versions (v4 and v5). All relevant content has already been migrated to /content/waf.

Keeping these obsolete files in the repo causes several problems:

1. Maintenance Overhead — Contributors must fix broken links and review irrelevant files during PRs, creating unnecessary work.
2. AI & Search Confusion — Our AI assistants and search systems index everything in the repo. Including outdated docs risks surfacing obsolete or conflicting information to users.
3. Content Governance — Retaining unused docs violates our “delete and archive boldly” principle and reduces clarity around what’s current and trustworthy.
4. No Dependency — A redirect from /nginx-app-protect/ to /waf/ is already in place, so removing the old content won’t impact users or SEO.

# General redirects
location ~^ /nginx-app-protect/ {
    return 301 /waf/;
}

Proposed Action

• Remove the entire /content/nap-waf directory from the repo.
• Verify that /content/waf contains all relevant, updated documentation.
• Confirm that no build scripts, navigation files, or indexes still reference /content/nap-waf.
• Test the /nginx-app-protect/ → /waf/ redirect to ensure it functions correctly after removal.

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Expected Outcomes

• Cleaner, easier-to-maintain documentation repo.
• Reduced friction in PR reviews and content updates.
• Improved accuracy of AI assistant and search results.
• Stronger alignment with content governance best practices.