Avoid macOS keychain in Section 0 helper

scripts/setup-section0-docs.sh

@@ -118,11 +118,15 @@ install_git_credential() {
   host="\$(credential_host "\$remote")"
   protocol="\$(printf "%s" "\$remote" | sed -n "s#^\\([^:/]*\\)://.*#\\1#p")"
   [ -n "\$protocol" ] || protocol="http"
-  if [ "\$(uname -s 2>/dev/null || true)" = "Darwin" ]; then
-    git -C "\$REPO_DIR" config credential.helper osxkeychain
-  fi
+  mkdir -p "\$SESSION_DIR"
+  credential_path="\$SESSION_DIR/git-credentials"
+  touch "\$credential_path"
+  chmod 600 "\$credential_path"
+  git -C "\$REPO_DIR" config --local --replace-all credential.helper ""
+  git -C "\$REPO_DIR" config --local --add credential.helper "store --file=\$credential_path"
   printf "protocol=%s\nhost=%s\nusername=%s\npassword=%s\n\n" "\$protocol" "\$host" "\$username" "\$password" \
     | git -C "\$REPO_DIR" credential approve
+  chmod 600 "\$credential_path"
 }
 
 auth_login() {
@@ -142,6 +146,13 @@ auth_login() {
   echo "Token check:"
   echo "  \$SERVER_URL/device/\$code/token"
   open_url "\$auth_url"
+  if [ "\${SECTION0_AUTH_POLL:-}" != "1" ]; then
+    echo "When the browser says login succeeded, return here and press Enter."
+    printf "Press Enter to finish login: "
+    IFS= read -r _section0_continue
+    auth_finish "\$code"
+    return
+  fi
   echo "Waiting for login..."
   token_json=""
   i=0