fix: restrict Linux native bindings install to Linux runners only

The setup-project action was force-installing Linux-specific npm binaries
(@rollup/rollup-linux-x64-gnu, @tailwindcss/oxide-linux-x64-gnu) on ALL
platforms including macOS and Windows. This overwrote the correct
platform-native binaries, causing Vite builds to fail on those runners,
which prevented any release assets from being uploaded.

Also removes the redundant `draft == false` condition from the upload job
(already guaranteed by `types: [published]` trigger) and adds an explicit
checkout step to the upload job for correctness.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.github/actions/setup-project/action.yml

@@ -45,6 +45,7 @@ runs:
       run: npm install --ignore-scripts --force
 
     - name: Install Linux native bindings
+      if: runner.os == 'Linux'
       shell: bash
       # Workaround for npm optional dependencies bug (npm/cli#4828)
       # Explicitly install Linux bindings needed for build tools