getDocsStaticPaths should use the same root index route convention as entryRouteUrl

[sansynx]

I found inconsistent route handling for the root docs entry

getDocsStaticPaths currently passes entry.id directly as the catch-all slug. For src/content/docs/index.mdx, that yields slug: index, and Astro builds the page at /index

Elsewhere Nimbus treats the same entry as the site root. entryRouteUrl("", "index") returns /, and the indexed entry, sidebar, and markdown helpers use that canonical URL

The current apps/www catch-all route works around this by translating slug: index to undefined, but packages/nimbus-starter-source/src/pages/[...slug].astro assigns getDocsStaticPaths directly and does not include that normalization

Could Nimbus choose one root-index contract and apply it consistently, preferably by normalizing the root entry in getDocsStaticPaths or by updating all helpers and templates to use /index? A small regression test for the starter template would make the expected route clear

Relevant code:

• https://github.com/cloudflare/nimbus/blob/main/packages/nimbus-docs/src/index.ts#L1002-L1016
• https://github.com/cloudflare/nimbus/blob/main/packages/nimbus-docs/src/_internal/astro-slug.ts#L42-L70
• https://github.com/cloudflare/nimbus/blob/main/apps/www/src/pages/%5B...slug%5D.astro#L17-L25
• https://github.com/cloudflare/nimbus/blob/main/packages/nimbus-starter-source/src/pages/%5B...slug%5D.astro

[sansynx]

I opened #111 with the shared route normalization and regression coverage.

[sansynx]

Checked current main and the root entry now maps to / in getDocsStaticPaths through #114, so this is sorted now