Add a reference page for the @harperfast/vite plugin (and fix stale package name)

### Gap

There is no reference documentation for the Vite/React integration. The only mention in the entire docs build is a single bullet in `reference/v5/components/overview.md` (~line 135) that:

1. has **no config examples** (no `config.yaml`, no `output`/`ssr` keys, no pairing-with-`static` contract), and
2. uses the **stale package name `@harperfast/vite-plugin`** — renamed to **`@harperfast/vite`** in v1.0.0.

### Impact

The `@harperfast/skills` rule `serving-web-content` cannot have its Vite/React half migrated to docs-generated (the static-files half already has good reference docs). Sourcing the current bullet as-is would also reintroduce the wrong package name. Part of the broader `create-harper` CLI docs cascade (see also `creating-harper-apps`).

### Suggested fix

Add an atomic reference page for `@harperfast/vite` covering: the `output`/`ssr` config keys, pairing with the `static` plugin (shared output dir is the only contract), SPA vs SSR `config.yaml`, dev (`harper dev`, middleware-mode HMR) vs prod (`harper run` → `vite build`) behavior, and the install command. Fix the stale package name in `components/overview.md`.

_{Filed while auditing rule/doc coverage for @harperfast/skills. sent with Claude Opus 4.8}

Start with reference/v5/components/overview.md and inspect the existing Vite/React bullet, then review nearby reference pages and the documented config.yaml conventions. Add the @harperfast/vite reference covering installation, output/ssr, static pairing, SPA versus SSR, and dev/prod behavior, and correct the stale package name in the overview page.

Written by the indexing model from the issue text.