feat(lsp): pull diagnostics, include links and folding ranges

Assisted-by: GLM 5.3 Flash

CHANGELOG.md

@@ -80,6 +80,10 @@ Unreleased changes on the `development` branch.
   `// func` signature while the cursor is on a `CALL`.
 - **LSP: document highlights**: every reference to the function or label
   under the cursor is highlighted.
+- **LSP: pull diagnostics** (`textDocument/diagnostic`), **#include
+  document links** (resolved against the document directory, then
+  `$GOROOT/pkg/include`, so `textflag.h` opens) and **folding ranges**
+  (one collapsible region per TEXT function body).
 - **Lint: `unused-label` rule.**  Flags labels that are defined but never
   referenced by any jump (Hint severity).
 - **Lint: `invalid-textflag` rule.**  Flags TEXT/GLOBL flags not in the