test(doctor): skip chmod-unreadable test as root too (Forgejo CI runs as root)

The Forgejo runner executes jobs as root, which bypasses chmod 0o000 — the
file stays readable so _check_config_file_paths reports passed=True and the
test's 'assert passed is False' fails. Extend the existing Windows skipif to
also skip when euid==0 (same rationale: chmod-based unreadability has no effect).
711/712 already green on Forgejo; this makes it 712.

Author: André Lange

tests/test_doctor.py

@@ -1,6 +1,7 @@
 """Tests for `cap doctor` command including deep checks."""
 
 import json
+import os
 import sys
 import tempfile
 from pathlib import Path
@@ -100,8 +101,8 @@ def test_config_file_paths_no_configs(self, tmp_home, monkeypatch):
         assert name == "Config file paths"
         assert passed is True
 
-    @pytest.mark.skipif(sys.platform == "win32",
-                        reason="chmod-based unreadability has no Windows equivalent")
+    @pytest.mark.skipif(sys.platform == "win32" or (hasattr(os, "geteuid") and os.geteuid() == 0),
+                        reason="chmod-based unreadability has no effect on Windows or as root (CI)")
     def test_config_file_paths_unreadable(self, tmp_home, monkeypatch):
         cf = tmp_home / ".claude.json"
         cf.write_text("{}")