fix: restore Effect.forkScoped for background upstream refresh

The merge from main incorrectly replaced Effect.forkScoped with
Effect.sync(() => { Effect.runFork(...) }), which creates a bare
runtime with no service layers. refreshCheckedOutBranchUpstream
calls executeGit, which depends on ChildProcessSpawner and other
contextual services that are unavailable under a naked Effect.runFork.
The error was silently swallowed by Effect.ignoreCause, causing stale
upstream tracking data after every branch checkout.

Author: cursoragent

apps/server/src/git/Layers/GitCore.ts

@@ -1941,11 +1941,9 @@ export const makeGitCore = Effect.fn("makeGitCore")(function* (options?: {
       });
 
       // Refresh upstream refs in the background so checkout remains responsive.
-      yield* Effect.sync(() => {
-        Effect.runFork(
-          refreshCheckedOutBranchUpstream(input.cwd).pipe(Effect.ignoreCause({ log: true })),
-        );
-      });
+      yield* Effect.forkScoped(
+        refreshCheckedOutBranchUpstream(input.cwd).pipe(Effect.ignoreCause({ log: true })),
+      );
     },
   );