fix(security): validate Bearer token value in MCP endpoints, not just presence

Previously any Bearer token (even invalid) passed the HTTP middleware and
got a session with access to tools/list and resources/list. Now the
OAuthRequiredMiddleware validates tokens against master key, API keys,
and OAuth JWT before allowing initialize.

Also fixes:
- WordPress Advanced env prefix: WORDPRESS_ → WORDPRESS_ADVANCED_ in docs
- Bump version to 3.0.1

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mcphub-server"
-version = "3.0.0"
+version = "3.0.1"
 description = "AI-native management hub for WordPress, WooCommerce, and self-hosted services via Model Context Protocol (MCP)"
 authors = [
     {name = "MCP Hub", email = "contact@mcphub.dev"}