Update all dependencies, remove dead code, legacy or unused / unmaintained MCP servers, update authors, cleanup potential insecure defaults, and add security warnings.

Summary

• Dependency updates: Updated all Python, Go, and Rust MCP server dependencies to latest versions
• Removed legacy code: Deleted deployment/ (ansible, terraform, k8s, knative), examples/deployment-configs/ - should be using the (maintained) helm charts for deployment
• Stale reference cleanup: Removed all dangling references to deleted paths across docs, scripts, pyproject.toml, and AGENTS.md
• Deployment docs: Updated minikube, ArgoCD, and Kubernetes docs to point to Helm charts (charts/mcp-stack) instead of removed raw manifests
• Author attribution: Audited and corrected author credits across all Python, Go, and Rust MCP server READMEs
• Bug fixes: Fixed broken test imports (python_sandbox_server), Containerfile CMD pointing to non-existent module (url_to_markdown_server), FastMCP version mismatch in README (mcp-rss-search), scipy version mismatch
  (data_analysis_server)
• Dead code removal: Removed empty stub directories from mcp_eval_server, dead "original server" references from url_to_markdown_server, dangling SIMILARITY.md reference from mcp-rss-search Makefile. Removed several unmaintained / legacy servers.
• Security warnings: Added sandbox/container isolation warnings and remote MCP server registration caution to main README, new mcp-servers/README.md, and all individual server READMEs