New internal/lsp package implements a minimal JSON-RPC 2.0 LSP server
over stdin/stdout with Content-Length framing. Supported lifecycle:
initialize → initialized → shutdown → exit. Document sync: Full (sends
complete text on every change). Handles textDocument/didOpen,
didChange, didSave, didClose; publishes textDocument/publishDiagnostics
after every change. Rule IDs surface as the diagnostic `code` field
with `"glint"` as source. Parse errors produce an Error diagnostic at
the top of the document. Include resolution is best-effort (GITLAB_TOKEN
env var; ~/.cache/glint default cache). CLI: glint lsp [--token]
[--gitlab-url] [--cache-dir] [--offline].
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
