fix: address Copilot review feedback for URI handler diagnostics

- Remove showWarningMessage to avoid double notification (wrapper already shows errors)
- Set granular failureStage markers at extractParams/handleRequest boundaries
- Remove redundant uriHasQuery and queryFragmentNonEmpty (uriQueryLength covers it)

Author: hanhan761

src/vscodeUriHandler.ts

@@ -68,18 +68,21 @@ export async function globalUriHandler(uri: vscode.Uri): Promise<void> {
         context.telemetry.properties.uriAuthority = uri.authority;
         context.telemetry.properties.uriPathLength = String(uri.path.length);
         context.telemetry.properties.uriQueryLength = String((uri.query ?? '').length);
-        context.telemetry.properties.uriHasQuery = uri.query ? 'true' : 'false';
 
         try {
             // Extract and validate parameters
             // Note: uri.query is already decoded once by VS Code when creating the vscode.Uri object
+            context.telemetry.properties.failureStage = 'extractParams';
             const params = extractAndValidateParams(context, uri.query);
 
             // Process the URI with user confirmation
+            context.telemetry.properties.failureStage = 'handleRequest';
             await handleConnectionStringRequest(context, params);
         } catch (error) {
             const errMsg = error instanceof Error ? error.message : String(error);
-            context.telemetry.properties.failureStage = 'unwrap';
+            if (!context.telemetry.properties.failureStage) {
+                context.telemetry.properties.failureStage = 'unknown';
+            }
             throw new Error(l10n.t('Failed to process URI: {0}', errMsg));
         }
     });
@@ -402,18 +405,9 @@ function extractAndValidateParams(context: IActionContext, queryFragment: string
     // Add sensitive values to valuesToMask to prevent sensitive data in logs
     maskParamsInTelemetry(context, params);
 
-    // Record whether the query was non-empty for diagnostic purposes.
-    context.telemetry.properties.queryFragmentNonEmpty = queryFragment ? 'true' : 'false';
-
     if (!params.connectionString) {
-        // Surface a user-visible message for the most common failure case
-        // instead of an opaque telemetry-only error.
-        void vscode.window.showWarningMessage(
-            l10n.t(
-                'A DocumentDB deep-link was opened without a connection string. Ensure the link includes a connectionString query parameter.',
-            ),
-        );
-        throw new Error(l10n.t('The connection string is required.'));
+        // Throw a descriptive error — the telemetry wrapper will surface it to the user.
+        throw new Error(l10n.t('A DocumentDB deep-link was opened without a connection string. Ensure the link includes a connectionString query parameter.'));
     }
 
     context.telemetry.properties.hasParamConnectionString = params.connectionString ? 'true' : undefined;