Replace NodeJS dict aliases with maps and named field reads

src/agents/opencode.ts

@@ -1,4 +1,4 @@
-import { isObject } from "#common";
+import { field, isObject } from "#common";
 import { AgentAuthError } from "#profiles";
 
 export function openCodeArgs(model: string, prompt: string): string[] {
@@ -56,13 +56,14 @@ export function openCodeError(output: string): Error | null {
     } catch {
       continue;
     }
-    if (!isObject(event)) continue;
-    const { type, error } = event;
-    if (type !== "error" || !isObject(error)) {
+    const error = field(event, "error");
+    if (field(event, "type") !== "error" || !isObject(error)) {
       continue;
     }
-    const { name, data } = error;
-    const { message, statusCode } = isObject(data) ? data : {};
+    const name = field(error, "name");
+    const data = field(error, "data");
+    const message = field(data, "message");
+    const statusCode = field(data, "statusCode");
     const detail = `opencode ${typeof name === "string" ? name : "error"}${
       typeof statusCode === "number" ? ` (API error ${statusCode})` : ""
     }: ${typeof message === "string" ? message : "unknown error"}`;
@@ -81,10 +82,9 @@ export function parseOpenCodeEvents(output: string): string {
   for (const line of output.split("\n")) {
     if (line.trim() === "") continue;
     const event: unknown = JSON.parse(line);
-    if (!isObject(event)) continue;
-    const { type, part } = event;
-    if (type !== "text" || !isObject(part)) continue;
-    const { text } = part;
+    const part = field(event, "part");
+    if (field(event, "type") !== "text" || !isObject(part)) continue;
+    const text = field(part, "text");
     if (typeof text === "string" && text.trim() !== "") result = text;
   }
   if (result === null) {