v0.11.0 — MCP media tools, LibreChat web UI, image pinning

New features:
- MCP server for image generation + TTS (generate_image, generate_tts)
  with dynamic model discovery, structured JSON returns, HybridS3 uploads
- LibreChat web UI at /librechat/ with LiteLLM backend and MCP tools
- All provider YAMLs annotated with model_info.mode for media models
- Resource calculator (recommend-limits.sh) covers all services

Infrastructure:
- All container images pinned to exact versions (no :latest)
- LibreChat MCP auth uses apiKey.source=admin (bypasses OAuth probe)
- New test suite for MCP media tools