routerMode: 'hash' navigation broken when using --base (regression in 52.16.0)

**Describe the bug** Since `52.16.0`, navigating between slides is broken when using `routerMode: 'hash'` and deploying to a sub-directory with `--base`. The fix from #2562 (prepending `import.meta.env.BASE_URL` to the route path in `getSlidePath`) assumes `routerMode: 'history'`, but breaks `'hash'` mode. With `createWebHashHistory`, Vue Router does **not** strip the base from paths passed to `router.push()`. The full base gets prepended to the hash fragment, producing an unmatchable route: ``` # Expected https://example.com/my-base/slides/#/4 # Actual (52.16.0 with routerMode: 'hash') https://example.com/my-base/slides/#/my-base/slides/4 ``` **Minimal reproduction** 1. Create a new Slidev project: `npm create slidev@latest` 2. Set `routerMode: 'hash'` in the frontmatter of `slides.md` 3. Build with a sub-directory base: `slidev build --base /my-base/slides/` 4. Serve the `dist/` folder and open the slides 5. Navigate to the next slide — the URL becomes `#/my-base/slides/2` instead of `#/2`, resulting in a 404/blank page **Root cause** `packages/client/logic/slides.ts` — `getSlidePath` now returns: ```ts return `${import.meta.env.BASE_URL}${path}` // e.g. "/my-base/slides/2" ``` This path is passed directly to `router.push({ path: ... })`. With `createWebHistory` the router strips the base and this works correctly. With `createWebHashHistory` the base is not stripped, so the full string lands in the hash fragment as an unresolvable route. **Environment** - Slidev version: 52.16.0 (regression from 52.14.2) - Browser: Chrome / Firefox - OS: Linux