v3.4.0 — vLLM wrapper (CPU + CUDA) + audiolla (CPU + CUDA, side-by-side) + /mcp/ aggregator fixes

Two new local services:

  VLLM=1 / VLLM_CUDA=1
                          — supervised `vllm serve` for text LLM +
                             embeddings (Nomic Embed v2 + Qwen3-0.6B by
                             default; flat HF-repo layout shared by CPU
                             and CUDA wrappers).
  AUDIOLLA=1 / AUDIOLLA_CUDA=1
                          — self-hosted audio-production REST + MCP
                             (psyb0t/docker-audiolla v0.23.1: Demucs, UVR,
                             librosa, basic-pitch, pyannote, CLAP,
                             fluidsynth, sox + ffmpeg DSP, workflow
                             presets + pipelines). CPU and CUDA run
                             side-by-side on /audiolla/ and
                             /audiolla-cuda/; both share the same weight
                             cache.

Also fixes /mcp/ aggregator for token-protected servers: the LiteLLM-side
`os.environ/X_AUTH_TOKEN` lookup resolves against the LiteLLM container's
env, so the AIGATE_TOKEN fallback chain has to be re-exported there.
FastMCP's DNS-rebinding protection (Host allowlist) is handled via a
static Host: 127.0.0.1:8000 header for both audiolla fragments. Tool-list
timeouts bumped to 120s for the larger MCP surfaces.

See CHANGELOG.md for the full details.