Environment:

• Slidev version: 52.16.0 (introduced in v52.16.0, worked correctly in v52.15.2)
• Browser: All

Describe the bug:

When building Slidev slides with --base /talks/<folder>/ and using $slidev.nav.next or $slidev.nav.go(), the router navigation results in duplicated base path in the URL.

Actual behavior:

• Initial URL: /talks/2026-06-30-xihuan/
• Click nav.next → /talks/2026-06-30-xihuan/talks/2026-06-30-xihuan/2 (WRONG - base duplicated)
• Expected: /talks/2026-06-30-xihuan/2 (CORRECT)

Root cause:

In v52.16.0, getSlidePath (packages/client/logic/slides.ts) was changed to include import.meta.env.BASE_URL:

// v52.15.2 and earlier:
return exporting ? `/export/${no}` : presenter ? `/presenter/${no}` : `/${no}`

// v52.16.0+:
return exporting ? `/export/${no}` : presenter ? `/presenter/${no}` : `${import.meta.env.BASE_URL}${no}`

Then in useNav.ts, the go() method does:

await router.push({
  path: getSlidePath(...), // already includes BASE_URL
  ...
})

But createWebHistory(BASE_URL) in setup/main.ts treats the path as relative and prepends the base again, causing duplication.

Reproduction:

pnpm exec slidev build --base /talks/2026-06-30-xihuan/ --out dist
# Serve with any static file server
# Navigate via $slidev.nav.next → URL will have duplicated base

Workarounds:

• Downgrade to v52.15.2 (last known working version)
• Use keyboard shortcuts (Space/Arrow) instead of $slidev.nav.next

Expected fix:
getSlidePath should return path segments without the base prefix, letting createWebHistory handle the base path automatically (like it does for createMemoryHistory and other router implementations).