feat: preserve diff context during LSP navigation

src/plugin.rs

@@ -140,6 +140,13 @@ pub struct CompletionItem {
     pub snippet: Option<CompletionSnippet>,
 }
 
+/// Native LSP range; each coordinate is (zero-based row, UTF-16 column).
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct Utf16Range {
+    pub start: (usize, usize),
+    pub end: (usize, usize),
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
 pub enum UpdateEffect {
@@ -162,6 +169,15 @@ pub enum UpdateEffect {
         row: usize,
         column: usize,
     },
+    /// Native LSP targets retain UTF-16 coordinates until their source text is resolved.
+    #[serde(skip_deserializing)]
+    NavigateUtf16 {
+        buffer_id: usize,
+        revision: u64,
+        path: PathBuf,
+        range: Utf16Range,
+        target_range: Option<Utf16Range>,
+    },
     Hover {
         buffer_id: usize,
         revision: u64,