fix(website): inject the fallback version instead of importing package.json

`website:lint` failed on master since the per-OS download pages landed:
`src/lib/downloads.ts` imported the workspace root `package.json` through a
relative path, which `@nx/enforce-module-boundaries` rejects ("external
resources cannot be imported using a relative or absolute path").

The value is only needed as a build-time constant for the offline fallback,
so `astro.config.mjs` now reads the root manifest through the file system
and injects `__IPTVNATOR_VERSION__` via Vite `define`; `downloads.ts` uses
that constant and `src/env.d.ts` declares its type. Verified with
`WEBSITE_SKIP_RELEASE_FETCH=1`: the built download pages link the
`iptvnator-<version>` assets and no define literal leaks into the output.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

apps/website/src/env.d.ts

@@ -0,0 +1,8 @@
+/// <reference types="astro/client" />
+
+/**
+ * Repository version from the workspace root `package.json`, injected at
+ * build time by `astro.config.mjs` through Vite `define`. Used by the download
+ * pages' offline fallback (`src/lib/downloads.ts`).
+ */
+declare const __IPTVNATOR_VERSION__: string;

apps/website/src/lib/downloads.ts

@@ -1,4 +1,3 @@
-import rootPackage from '../../../../package.json';
 import type { DownloadPlatform } from './platforms';
 
 /**
@@ -9,9 +8,13 @@ import type { DownloadPlatform } from './platforms';
  * exists, and so file sizes and the publish date can be shown. When the API
  * is unreachable (offline build, rate limit, `WEBSITE_SKIP_RELEASE_FETCH=1`)
  * the pages fall back to the repository version from the root `package.json`
+ * — injected as `__IPTVNATOR_VERSION__` by `astro.config.mjs`, since a
+ * relative import of the root manifest violates the Nx module boundaries —
  * and the known asset naming pattern from `electron-builder.json`.
  */
 
+const FALLBACK_VERSION = __IPTVNATOR_VERSION__;
+
 export const GITHUB_REPO = '4gray/iptvnator';
 export const REPO_URL = `https://github.com/${GITHUB_REPO}`;
 export const RELEASES_URL = `${REPO_URL}/releases`;
@@ -304,7 +307,7 @@ function normalizeAsset(value: unknown): ReleaseAsset[] {
 }
 
 function fallbackRelease(): ResolvedRelease {
-  const version = rootPackage.version;
+  const version = FALLBACK_VERSION;
   const tag = `v${version}`;
   const assets = Object.values(DOWNLOAD_OPTIONS)
     .flat()
@@ -323,5 +326,5 @@ function fallbackRelease(): ResolvedRelease {
 }
 
 function warnFallback(reason: string): void {
-  console.warn(`[website] Latest release lookup failed (${reason}); using package.json version ${rootPackage.version}.`);
+  console.warn(`[website] Latest release lookup failed (${reason}); using package.json version ${FALLBACK_VERSION}.`);
 }