fix(vcs): detect non-git repos in status commands via stderr check

When git status or rev-parse fails with a non-zero exit code in a
directory that is not a git repository, the stderr contains 'not a git
repository'. Previously the code would throw a GitCommandError with a
generic detail message, which prevented GitManager.isNotGitRepositoryError
from matching and returning isRepo: false.

Add stderr substring checks in readStatusDetailsLocal and
readStatusDetailsRemote to return the non-repository sentinel values,
consistent with listRefs.

Author: cursoragent

apps/server/src/vcs/GitVcsDriverCore.ts

@@ -1196,6 +1196,9 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       return NON_REPOSITORY_REMOTE_STATUS_DETAILS;
     }
     if (branchResult.exitCode !== 0) {
+      if (branchResult.stderr.toLowerCase().includes("not a git repository")) {
+        return NON_REPOSITORY_REMOTE_STATUS_DETAILS;
+      }
       return yield* new GitCommandError({
         ...gitCommandContext({
           operation: "GitVcsDriver.statusDetailsRemote.branch",
@@ -1316,6 +1319,9 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
     }
 
     if (statusResult.exitCode !== 0) {
+      if (statusResult.stderr.toLowerCase().includes("not a git repository")) {
+        return NON_REPOSITORY_STATUS_DETAILS;
+      }
       return yield* new GitCommandError({
         ...gitCommandContext({
           operation: "GitVcsDriver.statusDetails.status",