feat(navigation): add symbol index and LSP navigation features

The changes introduce a Tcl symbol index powering LSP navigation
features across the workspace. A navigation API exposes
snapshots and update hooks, enabling goto-definition,
references, and rename using the index. Background indexing
now watches Tcl files and rebuilds the index to stay in sync.

- Add Tcl symbol index and navigation snapshot API
- Wire go-to-definition, references, and rename using the index
- Watch Tcl files and refresh the index in the background

client/src/extension.ts

@@ -13,7 +13,8 @@ import {
     isFirstLineMachine,
     diagnosticHandler,
     cdlDocumentSymbolProvider,
-    defDocumentSymbolProvider
+    defDocumentSymbolProvider,
+    definitionCdlEventHandler
 } from "./common/handlers"
 import { registerLogger, traceError, traceLog, traceVerbose } from "./common/log/logging"
 import {
@@ -23,7 +24,7 @@ import {
     onDidChangePythonInterpreter,
     resolveInterpreter
 } from "./common/python"
-import { restartServer } from "./common/server"
+import { disposeServerResources, restartServer } from "./common/server"
 import { checkIfConfigurationChanged, getInterpreterFromSetting } from "./common/settings"
 import { loadServerDefaults } from "./common/setup"
 import { getLSClientTraceLevel } from "./common/utilities"
@@ -177,6 +178,16 @@ export async function activate(context: vscode.ExtensionContext) {
     )
     context.subscriptions.push(hoverCdlProvider)
 
+    const definitionCdlEventProvider = vscode.languages.registerDefinitionProvider(
+        { scheme: "file", language: "cdl" },
+        {
+            provideDefinition(document, position, token) {
+                return definitionCdlEventHandler(document, position, token)
+            }
+        }
+    )
+    context.subscriptions.push(definitionCdlEventProvider)
+
     const formatDefProvider = vscode.languages.registerDocumentFormattingEditProvider(
         { scheme: "file", language: "def" },
         {
@@ -246,7 +257,8 @@ export async function activate(context: vscode.ExtensionContext) {
 
 export function deactivate(): Thenable<void> | undefined {
     if (!client) {
+        disposeServerResources()
         return undefined
     }
-    return client.stop()
+    return client.stop().finally(disposeServerResources)
 }