fix(cli, fact-checker): per-stream stdio errors policy on Windows

Previously all three streams reconfigured to UTF-8 with errors='strict'.
That kills 'mempalace search' the moment a drawer carrying a surrogate
half (round-tripped from a filename via surrogateescape) hits print(),
losing the rest of the result block. Same hazard for warning lines on
stderr.

Split the policy:
  stdin  -> surrogateescape (malformed bytes from a redirected file
            survive as lone surrogates instead of crashing the read)
  stdout -> replace (drawer text with a stray surrogate becomes U+FFFD
            instead of UnicodeEncodeError mid-print)
  stderr -> replace (same protection for logger / warning paths)

Applied identically in the cli.py and fact_checker.py helpers; the DRY
extraction into a shared module is a separate cleanup ask, kept out of
this fix to keep the diff narrow.

Tests updated for the new per-stream assertion.

mempalace/cli.py

@@ -943,16 +943,32 @@ def _reconfigure_stdio_utf8_on_windows():
     content piped in (`mempalace search ... < query.txt`) or piped out
     (`mempalace search "..." > out.txt`) when verbatim drawer text or
     wing/room names contain non-Latin characters.
+
+    Per-stream errors policy:
+      stdin  -- surrogateescape: malformed bytes from a redirected file
+                survive as lone surrogates instead of crashing the read.
+      stdout -- replace: ``mempalace search`` prints verbatim drawer
+                text. A drawer that round-tripped a filename through
+                surrogateescape can hold a lone surrogate, which would
+                otherwise raise ``UnicodeEncodeError`` mid-print and
+                lose the rest of the search result block.
+      stderr -- replace: same hazard for logger output that quotes
+                user-supplied path or content.
     """
     if sys.platform != "win32":
         return
-    for name in ("stdin", "stdout", "stderr"):
+    policies = (
+        ("stdin", "surrogateescape"),
+        ("stdout", "replace"),
+        ("stderr", "replace"),
+    )
+    for name, errors in policies:
         stream = getattr(sys, name, None)
         reconfigure = getattr(stream, "reconfigure", None)
         if reconfigure is None:
             continue
         try:
-            reconfigure(encoding="utf-8", errors="strict")
+            reconfigure(encoding="utf-8", errors=errors)
         except Exception as exc:
             print(
                 f"WARNING: Could not reconfigure {name} to UTF-8: {exc}",

mempalace/fact_checker.py

@@ -309,18 +309,32 @@ def _reconfigure_stdio_utf8_on_windows():
     Without this, Python defaults stdio to the system ANSI codepage
     (cp1252/cp1251/cp950 depending on locale), which mojibakes
     non-ASCII fact text before pattern parsing sees it.
+
+    Per-stream errors policy mirrors the primary CLI helper in
+    ``mempalace/cli.py``:
+      stdin  -- surrogateescape: malformed input bytes survive as lone
+                surrogates instead of crashing the read.
+      stdout -- replace: extracted fact text can include surrogate
+                halves round-tripped from filenames; replace prevents
+                a UnicodeEncodeError mid-print.
+      stderr -- replace: same protection for warning lines.
     """
     import sys
 
     if sys.platform != "win32":
         return
-    for name in ("stdin", "stdout", "stderr"):
+    policies = (
+        ("stdin", "surrogateescape"),
+        ("stdout", "replace"),
+        ("stderr", "replace"),
+    )
+    for name, errors in policies:
         stream = getattr(sys, name, None)
         reconfigure = getattr(stream, "reconfigure", None)
         if reconfigure is None:
             continue
         try:
-            reconfigure(encoding="utf-8", errors="strict")
+            reconfigure(encoding="utf-8", errors=errors)
         except Exception as exc:
             print(
                 f"WARNING: Could not reconfigure {name} to UTF-8: {exc}",

tests/test_cli.py

@@ -1076,10 +1076,13 @@ def test_reconfigures_stdio_to_utf8_on_windows():
     ):
         _reconfigure_stdio_utf8_on_windows()
 
-    expected = {"encoding": "utf-8", "errors": "strict"}
-    assert stdin.reconfigure_calls == [expected]
-    assert stdout.reconfigure_calls == [expected]
-    assert stderr.reconfigure_calls == [expected]
+    # Per-stream errors policy: stdin survives bad bytes via
+    # surrogateescape so a redirected non-UTF-8 file does not crash
+    # the read; stdout/stderr use replace so a drawer carrying a
+    # round-tripped surrogate half does not crash mid-print.
+    assert stdin.reconfigure_calls == [{"encoding": "utf-8", "errors": "surrogateescape"}]
+    assert stdout.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+    assert stderr.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
 
 
 def test_reconfigure_stdio_is_noop_off_windows():

tests/test_fact_checker.py

@@ -318,10 +318,13 @@ class TestCLI:
         ):
             _reconfigure_stdio_utf8_on_windows()
 
-        expected = {"encoding": "utf-8", "errors": "strict"}
-        assert stdin.reconfigure_calls == [expected]
-        assert stdout.reconfigure_calls == [expected]
-        assert stderr.reconfigure_calls == [expected]
+        # Per-stream errors policy: stdin uses surrogateescape so a stray
+        # malformed byte from a redirected file does not crash the read,
+        # stdout/stderr use replace so an extracted fact carrying a
+        # surrogate half does not crash mid-print.
+        assert stdin.reconfigure_calls == [{"encoding": "utf-8", "errors": "surrogateescape"}]
+        assert stdout.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+        assert stderr.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
 
     def test_reconfigure_stdio_is_noop_off_windows(self):
         """Linux/macOS already default to UTF-8 stdio -- helper must not touch streams."""