Drop npm cache + use 'npm install' (no lock file in template)

setup-node with cache: 'npm' fails because the template ships without
package-lock.json. README documents the path to switch to 'npm ci' once
the downstream repo has a lock file.

.gitea/workflows/ci.yml

@@ -16,10 +16,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '22'
-          cache: 'npm'
+          # No `cache: 'npm'` here — the template ships without a lock file.
+          # Once your downstream repo has a package-lock.json from `npm install`,
+          # add `cache: 'npm'` back and switch the install step to `npm ci`.
 
-      - name: Install
+      - name: Install (use ci once lock file exists)
-        run: npm ci
+        run: npm install
 
       - name: Prisma generate (validates schema)
         run: npx prisma generate