feat: add TanStack Intent library and blog post (#743)

* feat: add tanstack/intent blog post

* feat: add TanStack Intent library and blog post header image

- Add Intent as a new library in the sidebar with landing page
- Add header image to the "From Docs to Agents" blog post
- Fix relative SVG image paths in blog post to use absolute paths

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* update blog post framing and Intent tagline

- Reframe closing as maintainer call-to-action with DB PR link
- Update Intent tagline and description

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* ci: apply automated fixes

* fix author name spelling

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: use @tanstack/intent for all CLI references in blog post

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Co-authored-by: Sarah Gerrard <98355961+LadyBluenotes@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: 4 people