collections-config.test.ts set currentIndexName to "myindex" in its
last test but only restored env vars in afterEach — not the module
variable. Under bun test (single process), this leaked into mcp.test.ts,
causing it to look for myindex.yml instead of index.yml.
Fix: reset setConfigIndexName("index") in afterEach, and add defensive
reset in mcp.test.ts beforeAll.