QVAC-18440 Add support to LLMs

[BrunoCampana]

What problem does this PR solve?

Currently, the support provided by the site for LLMs is low, limited to providing llms-full.txt, which is a dump of the entire site's content, and a lean llms.txt file with little content.

The goal of this PR is to change that, increasing support for LLMs in critical areas.

How does it solve it?

• We currently serve the llms.txt file, but its content basically redirected to the LLM for a full content dump.
• Now, llms.txt fulfills the role of site navigation, analogous to what the sidebar does for humans. It is automatically generated at build time.
• We keep llms-full.txt referenced in llms.txt.
• We added the generation of all pages in .md format. Now, an agent can access any page and obtain the content in markdown instead of HTML.
• We've added support for users to have buttons in the page action to: (1) copy the page content in markdown format, to paste into the context of their AI chat.

Other PR minors

• Fixed a bug in the nested links homepage.
• Added pkg http-server as a DevDependency to avoid downloading it every time the npm run serve command is used in the dev environment.

PR preview

https://qvac-docs-staging-fazwv-commit-bf106a9.kinsta.page

To test the new features:

1. Open any page on the site.
2. In the address bar, replace the trailing slash with .md.
3. Test the new "Copy page" button.

[kinsta]

Preview deployments for qvac-docs-staging ⚡️

Status	Branch preview	Commit preview
✅ Ready	Visit preview	Visit preview

Commit: bf106a915487efd107021f8fdf8269559cff4106

Deployment ID: 60c97ae8-1d1b-484f-b5eb-efc7b8c1d2f0

Static site name: qvac-docs-staging-fazwv

[github-actions]

Tier-based Approval Status

**PR Tier:** TIER1

**Current Status:** ✅ APPROVED

**Requirements:**
- 1 Team Member approval ✅ (1/1)
- 1 Team Lead OR Management approval ✅ (1/1)



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*This comment is automatically updated when reviews change.*

[BrunoCampana]

/review