fix(release): configure release workflow for npm publishing

- Delete existing release before creating new one to avoid conflicts
- Remove llmx-responses-api-proxy from dotslash config (not needed)
- Add 'Create GitHub Release' step to upload platform binaries
- Configure npm authentication by writing token to setup-node's .npmrc
- Use internal package identifier 'llmx' in workflow scripts

This fixes the release workflow to properly:
1. Clean up previous failed releases
2. Create GitHub release with all platform binaries
3. Add DotSlash manifest file (llmx) without conflicts
4. Publish to npm as @valknarthing/llmx with proper authentication

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/rust-release.yml

@@ -447,6 +447,18 @@ jobs:
             --release-version "${{ steps.release_name.outputs.name }}" \
             --package llmx
 
+      # Delete any existing release to avoid conflicts with dotslash manifest file
+      - name: Delete existing release if present
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          if gh release view "${{ github.ref_name }}" --repo "${{ github.repository }}" >/dev/null 2>&1; then
+            echo "Deleting existing release ${{ github.ref_name }}"
+            gh release delete "${{ github.ref_name }}" --repo "${{ github.repository }}" --yes
+          else
+            echo "No existing release found for ${{ github.ref_name }}"
+          fi
+
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v2
         with:
@@ -480,9 +492,6 @@ jobs:
         with:
           node-version: 22
           registry-url: "https://registry.npmjs.org"
-          scope: "@valknarthing"
-        env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
 
       - name: Download npm tarballs from release
         env:
@@ -499,10 +508,13 @@ jobs:
 
       - name: Publish to npm
         env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
           VERSION: ${{ needs.release.outputs.version }}
           NPM_TAG: ${{ needs.release.outputs.npm_tag }}
         run: |
+          # Write auth token to the .npmrc file that setup-node created
+          echo "//registry.npmjs.org/:_authToken=${{ secrets.NPM_TOKEN }}" >> ${NPM_CONFIG_USERCONFIG}
+
+
           set -euo pipefail
           tag_args=()
           if [[ -n "${NPM_TAG}" ]]; then