feat: add alphaview tool to show alpha weights alongside bar data

Joins the bar dataset with one or more alpha parquet files on (symbol, date)
for a given symbol and date range. Standalone tools/alphaview.py wired as
`cli.py alphaview`, plus README docs.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tools/alphaview.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""Show alpha weight(s) alongside daily bar data for a single symbol.
+
+Joins the bar dataset and one or more alpha parquet files on (symbol, date) so
+you can eyeball how a weight moves against price/volume over a time range.
+"""
+
+import click
+import pandas as pd
+
+
+def _filter_dates(df, start_date, end_date):
+    if start_date:
+        df = df[df["date"] >= pd.Timestamp(start_date)]
+    if end_date:
+        df = df[df["date"] <= pd.Timestamp(end_date)]
+    return df
+
+
+@click.command(name="alphaview")
+@click.option("--data-path", required=True, type=click.Path(exists=True), help="Bar dataset dir or parquet file")
+@click.option("--alpha-path", "alpha_paths", required=True, help="Comma-separated alpha parquet path(s)")
+@click.option("--symbol", required=True, help="Symbol id, e.g. sh600000")
+@click.option("--start-date", default=None, help="YYYY-MM-DD (inclusive)")
+@click.option("--end-date", default=None, help="YYYY-MM-DD (inclusive)")
+@click.option("-c", "--columns", default="close,volume", help="Comma-separated bar columns to show")
+def alphaview(data_path, alpha_paths, symbol, start_date, end_date, columns):
+    """Print bar columns + alpha weight(s) for SYMBOL over a date range."""
+    bar_cols = [c.strip() for c in columns.split(",") if c.strip()]
+
+    bars = pd.read_parquet(data_path)
+    bars = bars[bars["symbol_id"] == symbol]
+    if bars.empty:
+        raise click.ClickException(f"Symbol {symbol!r} not found in {data_path}")
+    missing = [c for c in bar_cols if c not in bars.columns]
+    if missing:
+        raise click.ClickException(f"Bar columns not found: {', '.join(missing)}")
+    bars = _filter_dates(bars, start_date, end_date)
+    out = bars[["date", *bar_cols]].set_index("date").sort_index()
+
+    for path in (p.strip() for p in alpha_paths.split(",") if p.strip()):
+        adf = pd.read_parquet(path)
+        adf = adf[adf["symbol_id"] == symbol]
+        adf = _filter_dates(adf, start_date, end_date)
+        # One alpha file may carry multiple alpha_name values; spread to columns.
+        wide = adf.pivot_table(index="date", columns="alpha_name", values="weight")
+        out = out.join(wide, how="left")
+
+    if out.empty:
+        raise click.ClickException("No rows in the requested date range")
+
+    with pd.option_context("display.max_rows", None, "display.max_columns", None, "display.width", None):
+        click.echo(f"symbol: {symbol}  rows: {len(out):,}")
+        click.echo(out.to_string())
+
+
+if __name__ == "__main__":
+    alphaview()