feat: support hoisted node_modules executables

[TrySound]

This is essential for monorepo projects where node_modules/.bin is not necessary the root.

Summary

• search from each config root to the nearest package-manager lockfile or Git root for node_modules/.bin executables
• preserve package-local precedence, global command fallback, existing workspace roots, and server-specific arguments
• support all language servers updated by feat: use node_modules local executable if available #4386, including hoisted tsgolint discovery for Oxlint

Testing

• make test
• stylua --check .
• bash .github/ci/lint.sh origin/master HEAD

make lint reaches EmmyLua but EmmyLua 0.25.0 reports two pre-existing errors in lsp/tinymist.lua and scripts/gen_annotations.lua, outside this change.