chore(site): pick up the new office-kit brand colors

[baseballyama]

Summary

Points the docs site at the site-kit commit that moves the family away from Microsoft's app color coding (office-kit/office-kit.github.io#2: pptx rose #d6336c, xlsx teal #0f8a8a, docx violet #6741d9), and replaces the favicon, touch icon and OG card with the versions regenerated there.

Motivation

Until now the product colors matched PowerPoint orange, Excel green and Word blue. The site-kit change only reaches this site once the lockfile points at the new mirror commit (e74a17d).

Changes

• pnpm-lock.yaml: site-kit at e74a17d
• site/static/: favicon, touch icon and OG card

Testing

• pnpm install --frozen-lockfile resolves the new site-kit (KitMark shows #d6336c)
• CI builds the site (a fresh worktree has no built @office-kit/docx dist for the site, so I did not build the site locally)

Breaking changes

None

Checklist

• I have read CLAUDE.md and followed the project's conventions.
• I have added or updated tests for the change. (colors only)
• I have added or updated documentation where user-visible behavior changed.
• If this is a breaking change, I have added a changeset / CHANGELOG entry and
  flagged it above.
• I have re-read my own diff and removed dead code, debug prints, and stale
  comments.
• If I used an LLM to draft this PR, I have verified each change myself, this
  PR represents real work that warrants a maintainer's review, and I am
  willing to defend each line in review.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LchrLbGcHU264nzZo63ZTP

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.