docs: add /skills landing page for Walrus agent skills

[jessiemongeon1]

Summary

• Add a /skills landing page at docs.wal.app/skills showcasing all skills from the MystenLabs/walrus-skills repo
• Follows the same architecture as docs.sui.io/skills: build-time JSON generation from GitHub with a committed fallback, category filter chips, copy-to-clipboard install command, and responsive card grid
• Uses Walrus design tokens (mint, violet, purple, tusk) for on-brand styling
• Walrus Memory is featured first with its own category tag
• Added "Skills" link to the navbar

Test plan

• Run pnpm start and verify /skills page renders with all 11 skill cards
• Verify category filter chips work (All, Walrus Memory, Get started, Build, Manage storage, Store and read)
• Verify "Walrus Memory" card appears first in the default view
• Verify copy button copies the install command
• Verify card links point to correct GitHub paths
• Run pnpm build and confirm no new broken links

🤖 Generated with Claude Code

[github-actions]

PR Preview Action v1.8.1
🚀 View preview at https://MystenLabs.github.io/walrus/pr-preview/pr-3489/
Built to branch gh-pages at 2026-06-25 21:35 UTC. Preview will be ready when the GitHub Pages deployment is complete.

[github-actions]

📋 afdocs check results

URL: https://MystenLabs.github.io/walrus/pr-preview/pr-3489/

Running checks on mystenlabs.github.io/walrus/pr-preview/pr-3489/...

Agent-Friendly Docs Check: https://MystenLabs.github.io/walrus/pr-preview/pr-3489/
Timestamp: 6/25/2026, 9:38:54 PM

content-discoverability
  ✓ llms-txt-exists: llms.txt found at https://MystenLabs.github.io/walrus/pr-preview/pr-3489/llms.txt
  ✓ llms-txt-valid: llms.txt follows the proposed structure (H1, blockquote, heading-delimited link sections)
  ⚠ llms-txt-size: llms.txt is 55,045 characters (between 50,000 and 100,000; consider splitting)
      Learn more: https://agentdocsspec.com/spec/#llms-txt-size
  ○ llms-txt-links-resolve: llms.txt contains 161 links, but none are under /walrus/pr-preview/pr-3489
  ○ llms-txt-links-markdown: llms.txt contains 161 links, but none are under /walrus/pr-preview/pr-3489
  ✓ llms-txt-directive-html: llms.txt directive found in HTML of all 169 pages, near the top of content
  ✗ llms-txt-directive-md: Could not fetch markdown for any of 169 pages; 169 had no markdown version
      Learn more: https://agentdocsspec.com/spec/#llms-txt-directive-md

markdown-availability
  ✗ markdown-url-support: No pages support .md URLs (0/169 tested)
      Learn more: https://agentdocsspec.com/spec/#markdown-url-support
  ✗ content-negotiation: Server ignores Accept: text/markdown header (0/169 pages return markdown)
      Learn more: https://agentdocsspec.com/spec/#content-negotiation

page-size
  ✓ rendering-strategy: All 169 pages contain server-rendered content
  ○ page-size-markdown: Skipped: dependency check did not pass
  ✓ page-size-html: All 169 pages under 50K chars (median 41K HTML → 8K markdown (80% boilerplate))
  ✗ content-start-position: 26 of 169 pages have content starting past 50% (worst 71%)
      Learn more: https://agentdocsspec.com/spec/#content-start-position

content-structure
  ✓ tabbed-content-serialization: 53 tab group(s) across 30 of 169 pages; all serialize under 50K chars
  ✓ section-header-quality: 2 page(s) with tab headers checked; headers include variant context
  ✓ markdown-code-fence-validity: All 0 code fences properly closed across 1 pages

url-stability
  ✓ http-status-codes: All 169 pages return proper error codes for bad URLs
  ✓ redirect-behavior: No redirects detected across 169 pages

observability
  ✗ llms-txt-coverage: llms.txt covers 0/161 sitemap doc pages (0%); 161 missing
      Learn more: https://agentdocsspec.com/spec/#llms-txt-coverage
  ○ markdown-content-parity: Skipped: dependency check did not pass
  ✓ cache-header-hygiene: All 170 endpoints have appropriate cache headers

authentication
  ✓ auth-gate-detection: All 169 pages are publicly accessible
  ○ auth-alternative-access: All docs pages are publicly accessible; no alternative access paths needed

Summary
  12 passed, 1 warnings, 5 failed, 5 skipped (23 total)

Full spec: https://agentdocsspec.com/spec/