Drop the redundant explicit build step from the release workflow

`pnpm run build` and pnpm publish's automatic prepack hook
(rm -rf .next && next build && rm -rf .next/cache) both ran a full
next build - the explicit step's output got thrown away and rebuilt
from scratch seconds later inside publish anyway. Kept only prepack's
build, since it's the one that actually has to succeed for a
publishable package to exist; a deterministic build that just passed
isn't going to fail differently a few steps later.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/release.yaml

@@ -25,7 +25,6 @@ jobs:
       - run: pnpm run typecheck
       - run: pnpm run format:check
       - run: pnpm run test
-      - run: pnpm run build
 
       - name: Set package version from the tag
         run: npm pkg set version="${GITHUB_REF_NAME#v}"