v2.4.0 — predictalot v0.2.1 (type-routed API + auth on /models)

Bumps docker-predictalot CPU + CUDA to v0.2.1. Flat /v1/forecast and
/v1/models endpoints are gone; each forecast type now has its own URL
family at /v1/<type>/{forecast,forecast/ensemble,models}. Breaking for
any direct-HTTP or MCP caller of predictalot — see CHANGELOG.md for
migration. MCP tool surface goes from 7 to 26 (per-(type,model) +
per-type ensemble + per-type listing).

Adds true multivariate forecasting, covariate-conditioned forecasting,
raw-sample-path forecasting, per-type ensembles, and an open /healthz
liveness probe. v0.2.1 closes a v0.2.0 information-leak by requiring
the bearer on all /v1/<type>/models endpoints.

Tests, docs, and the LiteLLM MCP description rewritten for the new
type-routed surface.