Navigation update - remove use case pop-out

[mnelsonBT]

Description

Updated navigation per DS team project "Short-term nav improvements + use case landing page "

• Restructures all five top-level nav sections to improve content discoverability and eliminate the nested 3-tier use case flyout menu
• Files changed: buildNavigation.ts, common.json (translation keys only). No changes to any rendering components; the nav UI is fully data-driven from buildNavigation(). The CrawlableNav server component, desktop Menu, and mobile MobileMenu all automatically reflect the new structure.
• No orphan pages: 10 use-case pages lose direct nav links but remain accessible via /use-cases/ landing page, internal cross-links, and sitemap
  13 pages gain nav visibility for the first time (bug-bounty, trillion-dollar-security, energy-consumption, foundation, assets, community/support, community/get-involved, etc.)

Deviation from DS team project:

• "/developers/local-environment/" removed from build nav as it redirects to "/developers/tools/" in the redirect config

Note:

• PR AI content updates #17994 'AI content updates' introduces the AI-related changes included in the original DS team project scope:
  • Adds the AI builder hub navigation under 'build'
  • Replaces 'AI agents' under use cases with 'decentralized AI'
  • Pending PR merge timing, new nav will have to be caught up to the AI PR, or the AI PR will have to be caught up to the new nav

Related Issue

See DS team project "Short-term nav improvements + use case landing page"

[netlify]

✅ Deploy Preview for ethereumorg ready!

Name	Link
🔨 Latest commit	a820c7a
🔍 Latest deploy log	https://app.netlify.com/projects/ethereumorg/deploys/69f0b5047d9b100008d24ea1
😎 Deploy Preview	https://deploy-preview-18058.ethereum.it
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	7 paths audited Performance: 72 (🟢 up 23 from production) Accessibility: 93 (no change from production) Best Practices: 100 (no change from production) SEO: 98 (🔴 down 1 from production) PWA: 59 (no change from production) View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[pettinarip]

@mnelsonBT two small comments. LGTM!

[pettinarip]

Suggested change

	"nav-find-l2-label": "Find a L2 network",
	"nav-find-l2-label": "Find an L2 network",

[pettinarip]

not blocking but after removing the old structure, there may be some orphan translation keys in the common namespace. The nav-* keys in particular are worth double checking for cleanup