fix(mcp): rename @webclaw/mcp bin to avoid npx PATH shadowing

The published bin was named `webclaw-mcp`, which npx shadows with any existing
`webclaw-mcp` on PATH (Homebrew/cargo/create-webclaw) — so `npx @webclaw/mcp`
silently ran a stale binary instead of the launcher, for exactly our existing
CLI users. Rename the bin to the unique `webclaw-mcp-launcher`; `npx
@webclaw/mcp` still resolves the single bin. Verified end-to-end: with a stale
webclaw-mcp on PATH, npx now runs the launcher and returns 14 tools.

- bin: webclaw-mcp -> webclaw-mcp-launcher; version 0.6.15 -> 0.6.16
- mark webclaw-mcp.mjs executable
- release.yml: version the launcher INDEPENDENTLY of the core release (a
  launcher-only fix must ship without a core bump) — publish the next patch
  above the current npm version and pin RELEASE_TAG to the release tag
- server.json: sync to 0.6.16

Published + deprecated 0.6.15 (bin collision); 0.6.16 is the first good release.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -209,15 +209,16 @@ jobs:
         env:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
         run: |
-          tag="${GITHUB_REF#refs/tags/}"   # e.g. v0.6.16
-          ver="${tag#v}"                   # 0.6.16
-          # Lockstep versioning: @webclaw/mcp@X.Y.Z installs the webclaw vX.Y.Z
-          # release. Both the pinned binary tag and the npm version derive from
-          # the git tag, so no commit-back is needed and the published package
-          # always points at matching, already-uploaded release assets.
+          tag="${GITHUB_REF#refs/tags/}"   # e.g. v0.6.17 (core release)
+          # Pin which prebuilt binary this launcher downloads to the just-released tag.
           sed -i -E "/const RELEASE_TAG =/ s|\"v[0-9.]+\"|\"${tag}\"|" webclaw-mcp.mjs
-          npm version "$ver" --no-git-tag-version --allow-same-version
-          echo "publishing @webclaw/mcp@${ver} pinned to ${tag}:"
+          # The launcher is versioned INDEPENDENTLY of the core release (a
+          # launcher-only fix must be shippable without a core bump). Publish the
+          # next patch above whatever is currently on npm — no commit-back needed.
+          cur="$(npm view @webclaw/mcp version 2>/dev/null || echo 0.0.0)"
+          npm version "$cur" --no-git-tag-version --allow-same-version >/dev/null
+          npm version patch --no-git-tag-version >/dev/null
+          echo "publishing @webclaw/mcp@$(node -p "require('./package.json').version") pinned to ${tag}:"
           grep -n "RELEASE_TAG =" webclaw-mcp.mjs
           npm publish --access public