Expand description
L4b (lsp-architecture.md §15): host-side lattice_lsp::modes::DiagnosticsQuery
impl backing lsp-diagnostics-mode’s mode-owned gl handler.
The mode handler (in lattice-lsp) has only ctx.buffer_id +
ctx.cursor + the service registry — it cannot resolve a buffer to
its LSP URI (that map is editor-local). This impl closes that gap:
it reads the live published RenderState snapshot, resolves
buffer_id → uri through buffers.uris, and queries the
DiagnosticsLayer — all without exposing a host method or the URI
map to the mode. Registered once at boot under
lattice_lsp::modes::DiagnosticsQueryHandle.