fix Windows Docker sandbox path mounting (#1634)

* fix windows docker sandbox paths

* fix windows sandbox mount validation

* fix backend checks for windows sandbox path PR

backend/tests/test_docker_sandbox_mode_detection.py

@@ -11,9 +11,16 @@ import pytest
 
 REPO_ROOT = Path(__file__).resolve().parents[2]
 SCRIPT_PATH = REPO_ROOT / "scripts" / "docker.sh"
-BASH_EXECUTABLE = which("bash") or r"C:\Program Files\Git\bin\bash.exe"
+BASH_CANDIDATES = [
+    Path(r"C:\Program Files\Git\bin\bash.exe"),
+    Path(which("bash")) if which("bash") else None,
+]
+BASH_EXECUTABLE = next(
+    (str(path) for path in BASH_CANDIDATES if path is not None and path.exists() and "WindowsApps" not in str(path)),
+    None,
+)
 
-if not Path(BASH_EXECUTABLE).exists():
+if BASH_EXECUTABLE is None:
     pytestmark = pytest.mark.skip(reason="bash is required for docker.sh detection tests")
 
 
@@ -21,13 +28,14 @@ def _detect_mode_with_config(config_content: str) -> str:
     """Write config content into a temp project root and execute detect_sandbox_mode."""
     with tempfile.TemporaryDirectory() as tmpdir:
         tmp_root = Path(tmpdir)
-        (tmp_root / "config.yaml").write_text(config_content)
+        (tmp_root / "config.yaml").write_text(config_content, encoding="utf-8")
 
         command = f"source '{SCRIPT_PATH}' && PROJECT_ROOT='{tmp_root}' && detect_sandbox_mode"
 
         output = subprocess.check_output(
             [BASH_EXECUTABLE, "-lc", command],
             text=True,
+            encoding="utf-8",
         ).strip()
 
         return output
@@ -37,7 +45,11 @@ def test_detect_mode_defaults_to_local_when_config_missing():
     """No config file should default to local mode."""
     with tempfile.TemporaryDirectory() as tmpdir:
         command = f"source '{SCRIPT_PATH}' && PROJECT_ROOT='{tmpdir}' && detect_sandbox_mode"
-        output = subprocess.check_output([BASH_EXECUTABLE, "-lc", command], text=True).strip()
+        output = subprocess.check_output(
+            [BASH_EXECUTABLE, "-lc", command],
+            text=True,
+            encoding="utf-8",
+        ).strip()
 
     assert output == "local"