Add empty-stdout guard in listChangeRequests for non-open state

When GitHub CLI returns empty stdout (e.g. network issue, partial response),
return an empty array instead of attempting JSON parse. This restores the
resilient behavior from the old findLatestPr code, which used 'continue' to
skip empty responses and try the next head selector.

Author: cursoragent

apps/server/src/sourceControl/GitHubSourceControlProvider.ts

@@ -76,8 +76,12 @@ export const make = Effect.fn("makeGitHubSourceControlProvider")(function* () {
         ],
       })
       .pipe(
-        Effect.flatMap((result) =>
-          Effect.sync(() => decodeGitHubPullRequestListJson(result.stdout.trim())).pipe(
+        Effect.flatMap((result) => {
+          const raw = result.stdout.trim();
+          if (raw.length === 0) {
+            return Effect.succeed([]);
+          }
+          return Effect.sync(() => decodeGitHubPullRequestListJson(raw)).pipe(
             Effect.flatMap((decoded) =>
               Result.isSuccess(decoded)
                 ? Effect.succeed(
@@ -95,8 +99,8 @@ export const make = Effect.fn("makeGitHubSourceControlProvider")(function* () {
                     }),
                   ),
             ),
-          ),
-        ),
+          );
+        }),
         Effect.mapError((error) =>
           Schema.is(SourceControlProviderError)(error)
             ? error