MCP server config already resolves Cursor-style ${env:VAR} references
(mcp_tool._env_ref_name); config.yaml's expander treated the same shape
as a literal string — a confusing half-support. _expand_env_vars() now
strips the env: prefix and resolves identically, _env_ref_snapshot()
tracks the ref under the REAL var name (preserving the #58514 cache-
invalidation contract), and refs with a non-env source prefix
(bitwarden:/vault:/file:) warn with a pointer to the secrets: block
instead of being silently treated as a variable named 'bitwarden:FOO'.
Salvaged from PR #59516 — the audit-CLI half and the main() exit-code
change were out of scope and are not included.
Co-authored-by: andynguyendk <35395190+andynguyendk@users.noreply.github.com>
