fix(release): use GITHUB_TOKEN for GitHub Packages npm auth, drop app token

[asachs01]

Problem

ninjaone-mcp v2.0.0 (first real release through the a61021d pipeline) failed at Build and Push Docker Image:

npm error 403 403 Forbidden - GET https://npm.pkg.github.com/download/@wyre-technology/node-ninjaone/1.1.2/...
npm error 403 Permission installation not allowed to Read organization package

Downstream Publish to MCP Registry, Security Scan, and deploy all skipped, so v2.0.0 has a tag/GitHub release but no image and no registry entry. Run: https://github.com/wyre-technology/ninjaone-mcp/actions/runs/28712238040

Root cause

The npm registry does not accept custom GitHub App installation tokens for cross-repo package reads — the minted app token is refused even though the app has packages: read org-wide and the package is public.

The a61021d app-token approach was itself a fix for a mis-diagnosed 403: the release job's permissions: block grants contents: write + issues: write but not packages: read, so its GITHUB_TOKEN was being denied. The app-token detour never got exercised until today because every fleet release since 06-26 was a no-op (docker skipped), so the latent failure surfaced only now.

Fix

Use GITHUB_TOKEN for npm auth everywhere in mcp-server-release.yml, matching the canonical pattern mcp-assert.yml already uses:

• release job: add packages: read to permissions; npm ci with NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}; drop the app-token mint step.
• docker job: build the npmrc secret and NODE_AUTH_TOKEN/GITHUB_TOKEN build-args from secrets.GITHUB_TOKEN (the job already has packages: write for the ghcr push); drop the app-token mint step.

Evidence the fix works

mcp-assert.yml uses exactly this pattern (permissions: packages: read + NODE_AUTH_TOKEN: secrets.GITHUB_TOKEN) and successfully installed @wyre-technology/node-ninjaone@2.0.0 cross-repo today on ninjaone-mcp#57 — a version published minutes earlier, so it was a genuine registry download, not a cache hit.

Follow-ups after merge

• Every *-mcp repo pins the reusable by SHA (@a61021de) and needs a re-pin to this commit before its next real release. I'll start with ninjaone-mcp (blocked release) — the rest of the fleet can follow.
• Caveat documented in-file: this relies on the SDK packages being public. A private SDK package would need a "Manage Actions access" grant for each consuming repo.