fix(git-sync): force git rm --cached to handle MM index state

After reset --mixed FETCH_HEAD, staged content can differ from both
HEAD and the working tree when new file content has been written.
Without -f, git rm --cached refuses to remove such entries.

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

services/web/app/src/Features/GitSync/GitSyncHandler.mjs

@@ -259,7 +259,7 @@ async function pushToRemote(
   // skipped by git add -A when the directory mtime hasn't changed since the last checkout.
   if (pushFiles) {
     if (subPath) {
-      await spawnGit(['rm', '-r', '--cached', '--ignore-unmatch', '--', subPath], repoDir)
+      await spawnGit(['rm', '-rf', '--cached', '--ignore-unmatch', '--', subPath], repoDir)
       await spawnGit(['add', '--', subPath], repoDir)
     } else {
       await spawnGit(['add', '-A'], repoDir)