Problem: lua-language-server --check lua/ treats lua/ as its workspace
root and fails to find .luarc.json in the project root, so diagnostics
globals (vim, jit) are not loaded and every vim.* reference is flagged
as undefined-global.
Solution: pass --configpath .luarc.json explicitly, matching what the
GitHub CI action already does.
Problem: reload_spec.lua called io.open() without nil checks, causing
need-check-nil warnings. Adding ${3rd}/busted and ${3rd}/luassert to
workspace.library caused lua-language-server 3.7.4 to run diagnostics
on its own bundled meta files, surfacing pre-existing cast-local-type
bugs in luassert's annotations that are not ours to fix.
Solution: use assert(io.open(...)) in reload_spec.lua to satisfy the
nil check. Remove busted/luassert library paths from .luarc.json since
they only benefit spec/ which is not type-checked in CI. Narrow the
lua-language-server check in scripts/ci.sh to lua/ to match CI.
