ci: build with npm + Node 22 so Sharp installs (fixes bun segfault + missing-sharp)

bun --bun crashed Bun runtime (SIGILL); plain bun run hit missing Sharp
native binary for astro:assets. npm install pulls @img/sharp-linux-x64
reliably.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -11,16 +11,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install Bun
-        uses: oven-sh/setup-bun@v2
+      - name: Setup Node
+        uses: actions/setup-node@v4
         with:
-          bun-version: latest
+          node-version: 22
 
+      # npm (not bun) so Sharp's native binary for astro:assets image
+      # optimization installs reliably on the runner
       - name: Install dependencies
-        run: bun install
+        run: npm install
 
       - name: Build site
-        run: bun --bun run build
+        run: npm run build
 
       - name: Deploy dist/ to CT148 over SSH
         env: