Fix Windows CI test failures: headless PromptSession + /tmp path

- Wrap fallback PromptSession() in try/except so headless Windows CI
  gracefully falls back to input() instead of crashing
- Use tempfile.gettempdir() instead of hardcoded /tmp/ in sandbox test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Hmbown

src/nemocode/cli/commands/repl.py

@@ -90,7 +90,10 @@ def __init__(self) -> None:
                 self._session = PromptSession(history=history)
             except Exception:
                 # If history file is unwritable or any other issue, run without history
-                self._session = PromptSession()
+                try:
+                    self._session = PromptSession()
+                except Exception:
+                    pass  # No terminal available (e.g. Windows CI) — fall back to input()
 
     async def read(self, mode: str = "code") -> str | None:
         """Read user input. Returns None on EOF (Ctrl+D). Raises KeyboardInterrupt on Ctrl+C."""

tests/test_sandbox.py

@@ -56,7 +56,8 @@ async def test_write_inside_project_allowed(self, tmp_path):
     async def test_edit_outside_project_rejected(self, tmp_path):
         set_project_root(tmp_path)
         # Create a file outside the project
-        outside = Path("/tmp/nemocode_test_outside.txt")
+        import tempfile
+        outside = Path(tempfile.gettempdir()) / "nemocode_test_outside.txt"
         outside.write_text("original")
         try:
             result = await edit_file(str(outside), "original", "modified")