fix: complete getMethodsFromService for TS 5.9 and hey-api 0.90.1

- Use Identifier.text instead of getText() for robust HTTP method name extraction
- Fix JSDoc extraction by searching from VariableStatement level instead of ArrowFunction
- Update tests/utils.ts to use hey-api 0.90.1 plugins API
- Update test snapshots to include correctly extracted JSDoc comments

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: TakehiroTada

src/service.mts

@@ -80,7 +80,7 @@ export function getMethodsFromService(node: SourceFile): FunctionDescription[] {
       if (ts.isCallExpression(callExpression)) {
         const expr = callExpression.expression;
         if (ts.isPropertyAccessExpression(expr)) {
-          httpMethodName = expr.name.getText();
+          httpMethodName = (expr.name as ts.Identifier).text;
         }
       }
 
@@ -97,7 +97,7 @@ export function getMethodsFromService(node: SourceFile): FunctionDescription[] {
         return [tsNode];
       };
 
-      const children = getAllChildren(arrowFunction);
+      const children = getAllChildren(variableStatement.compilerNode);
       // get all JSDoc comments
       // this should be an array of 1 or 0
       const jsDocs = children