move cli script to reduce core package dependencies

src/smithycmd.py

@@ -0,0 +1,86 @@
+# /// script
+# requires-python = ">=3.13"
+# dependencies = [
+#     "click>=8.4.1",
+#     "rich>=15.0.0",
+#     "polars>=1.40.1"
+# ]
+# ///
+import click
+
+from rich.console import Console
+from rich.table import Table
+from rich.panel import Panel
+
+from smithy import smith_set
+
+@click.command()
+@click.argument("spreadsheet", type=click.Path(exists=True, dir_okay=False))
+def cli(spreadsheet: str) -> None:
+    """
+    Compute the Smith set from a ranked-choice ballot spreadsheet.
+
+    The Smith set is the minimal set of candidates which can beat all others pairwise - if there is a single winner
+    in the set they are guaranteed the Condorcet i.e. Majority winner.
+    """
+
+    console = Console()
+
+    try:
+        # Load spreadsheet
+        if spreadsheet.endswith(".csv"):
+            df = pl.read_csv(spreadsheet)
+
+        elif spreadsheet.endswith((".xlsx", ".xls")):
+            df = pl.read_excel(spreadsheet)
+
+        else:
+            console.print(
+                "[bold red]Unsupported file type.[/bold red]\nUse CSV or Excel."
+            )
+            raise SystemExit(1)
+
+        # Normalize numerical dataframe entries
+        df = df.with_columns(
+            [
+                pl.col(c)
+                .cast(pl.Utf8)
+                .str.strip_chars()
+                .cast(pl.Int64, strict=False)
+                .fill_null(0)
+                for c in df.columns
+            ]
+        )
+
+        # Compute Smith set
+        smiths = smith_set(df)
+
+        # Preview table
+        preview = Table(title="Ballot Box")
+
+        for col in df.columns:
+            preview.add_column(col)
+
+        for row in df.head(5).iter_rows():
+            preview.add_row(*map(str, row))
+
+        console.print(preview)
+
+        # Results
+        console.print()
+
+        console.print(
+            Panel.fit(
+                "\n".join(f"• {c}" for c in smiths),
+                title="Resulting Smith Set",
+                border_style="green",
+            )
+        )
+
+    except Exception as e:
+        console.print(f"[bold red]Error:[/bold red] {e}")
+
+        raise SystemExit(1)
+
+if __name__ == "__main__":
+    cli()