Generate a combined Rivet skill and discovery index

[NathanFlurry]

Rivet already publishes four product skills, but clients cannot discover them through the conventional skills index. Generate a combined rivet skill containing every product's documentation and example links, and publish a single-entry /.well-known/agent-skills/index.json with its SHA-256 digest during the existing prebuild step.

Keep the product skill output unchanged, use absolute OpenAPI links in the combined skill, and serve the new files with the required content types and public caching. The existing skills publishing workflow also exports the combined skill.

Validation:

• Full Astro production build using the committed vendor docs.
• Confirmed all four product skills remain byte-identical to the previous renderer, and all documentation/example links appear in the combined skill.
• Verified the single-entry discovery format and digest against the generated file and served bytes.
• Validated the production Caddy configuration and checked GET/HEAD responses for JSON/Markdown content types and caching.

[railway-app]

🚅 Deployed to the website-pr-62 environment in rivet-website

Service	Status	Web	Updated
website	😴 Sleeping (View Logs)	Web	Sep 16, 2026 at 8:33 pm UTC

[the-company-company]

✅ No issues found

_{Reviewed commit b3620ba.}