v0.54.0 — Vendored zvec 0.7.2 and the shared model tree closes

[0.54.0] - 2026-10-21

The Docker build links the vendored zvec 0.7.2 crates

• The vendored zvec Rust crates were still 0.7.1 while the Cargo tag resolves
  0.7.2, so the Docker [patch] no longer matched and the build silently fell
  back to fetching the git dependency (the patch was not used warning). The
  vendor tree now holds the v0.7.2 crates, VENDOR.md records the new tag, and
  ARG ZVEC_RUST_VERSION points at the matching prebuilt release, so the patch
  applies and the build stays self-contained.

The shared model tree closes

• All in-scope consumers of the shared provider/instance/model selector are
  covered: dataset create and configuration, retrieval-test rerank, memory
  list and detail embedding/LLM, skills search configuration, the search page
  rerank field, the search-app detail rerank field and the six default-model
  fields. The remaining upstream consumer files are reference material by
  project scope (RayRAG serves a Rust-native management surface).