docs: replace MkDocs with Zensical (#3073)

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com>

.github/workflows/deploy-docs.yml

@@ -14,6 +14,7 @@ on:
       - src/mcp/**
       - src/mcp-types/**
       - scripts/build-docs.sh
+      - scripts/docs/**
       - pyproject.toml
       - uv.lock
       - .github/workflows/deploy-docs.yml
@@ -49,9 +50,6 @@ jobs:
 
       - name: Build combined docs (v1.x at /, main at /v2/)
         run: bash scripts/build-docs.sh site
-        env:
-          # Silence mkdocs-material's MkDocs 2.0 warning banner in CI logs.
-          NO_MKDOCS_2_WARNING: "1"
 
       - name: Configure Pages
         uses: actions/configure-pages@45bfe0192ca1faeb007ade9deae92b16b8254a0d # v6.0.0