Merge main and revert user-visible UI string in llm_assist.py

Resolve merge conflict in install_python_stack.py (keep _safe_print from
main). Revert one user_notification string back to em dash -- it renders
in the browser Dataset Preview dialog.

studio/backend/utils/datasets/llm_assist.py

@@ -645,7 +645,7 @@ def _run_multi_pass_advisor(
                 "is_conversational": True,
                 "user_notification": (
                     "This dataset is already in conversational format. "
-                    "No conversion needed -- columns can be mapped directly."
+                    "No conversion needed — columns can be mapped directly."
                 ),
             }
 

studio/install_python_stack.py

@@ -44,6 +44,39 @@ LOCAL_DD_UNSTRUCTURED_PLUGIN = (
     SCRIPT_DIR / "backend" / "plugins" / "data-designer-unstructured-seed"
 )
 
+# -- Unicode-safe printing ---------------------------------------------
+# On Windows the default console encoding can be a legacy code page
+# (e.g. CP1252) that cannot represent Unicode glyphs such as ✅ or ❌.
+# _safe_print() gracefully degrades to ASCII equivalents so the
+# installer never crashes just because of a status glyph.
+
+_UNICODE_TO_ASCII: dict[str, str] = {
+    "\u2705": "[OK]",  # ✅
+    "\u274c": "[FAIL]",  # ❌
+    "\u26a0\ufe0f": "[!]",  # ⚠️  (warning + variation selector)
+    "\u26a0": "[!]",  # ⚠  (warning without variation selector)
+}
+
+
+def _safe_print(*args: object, **kwargs: object) -> None:
+    """Drop-in print() replacement that survives non-UTF-8 consoles."""
+    try:
+        print(*args, **kwargs)
+    except UnicodeEncodeError:
+        # Stringify, then swap emoji for ASCII equivalents
+        text = " ".join(str(a) for a in args)
+        for uni, ascii_alt in _UNICODE_TO_ASCII.items():
+            text = text.replace(uni, ascii_alt)
+        # Final fallback: replace any remaining unencodable chars
+        print(
+            text.encode(sys.stdout.encoding or "ascii", errors = "replace").decode(
+                sys.stdout.encoding or "ascii", errors = "replace"
+            ),
+            **kwargs,
+        )
+
+
+
 # -- Color support ------------------------------------------------------
 
 
@@ -119,7 +152,7 @@ def run(
         stderr = subprocess.STDOUT if quiet else None,
     )
     if result.returncode != 0:
-        print(_red(f"❌ {label} failed (exit code {result.returncode}):"))
+        _safe_print(_red(f"❌ {label} failed (exit code {result.returncode}):"))
         if result.stdout:
             print(result.stdout.decode(errors = "replace"))
         sys.exit(result.returncode)
@@ -267,7 +300,9 @@ def patch_package_file(package_name: str, relative_path: str, url: str) -> None:
         text = True,
     )
     if result.returncode != 0:
-        print(_red(f"   ⚠️  Could not find package {package_name}, skipping patch"))
+        _safe_print(
+            _red(f"   ⚠️  Could not find package {package_name}, skipping patch")
+        )
         return
 
     location = None
@@ -277,7 +312,7 @@ def patch_package_file(package_name: str, relative_path: str, url: str) -> None:
             break
 
     if not location:
-        print(_red(f"   ⚠️  Could not determine location of {package_name}"))
+        _safe_print(_red(f"   ⚠️  Could not determine location of {package_name}"))
         return
 
     dest = Path(location) / relative_path
@@ -393,7 +428,7 @@ def install_python_stack() -> int:
 
     # 11. Local Data Designer seed plugin
     if not LOCAL_DD_UNSTRUCTURED_PLUGIN.is_dir():
-        print(
+        _safe_print(
             _red(
                 f"❌ Missing local plugin directory: {LOCAL_DD_UNSTRUCTURED_PLUGIN}",
             ),
@@ -422,7 +457,7 @@ def install_python_stack() -> int:
         stderr = subprocess.DEVNULL,
     )
 
-    print(_green("✅ Python dependencies installed"))
+    _safe_print(_green("✅ Python dependencies installed"))
     return 0