feat(cli): add Rich output formatters

Add formatters for validation results (table/json/simple) and
benchmark history display with regression report panels.

src/veritext/cli/formatters.py

@@ -0,0 +1,170 @@
+"""Rich output formatters for CLI display."""
+
+import json
+
+from rich.console import Console
+from rich.panel import Panel
+from rich.table import Table
+
+from veritext.benchmark.models import BenchmarkRun, RegressionReport
+
+console = Console()
+
+
+def format_validation_table(
+    results: dict[str, float],
+    threshold: float | None = None,
+) -> Table:
+    """
+    Format validation results as a Rich table.
+
+    Args:
+        results: Dictionary of metric names to scores.
+        threshold: Optional threshold for pass/fail colouring.
+
+    Returns:
+        Rich Table object.
+    """
+    table = Table(title="Validation Results", show_header=True, header_style="bold")
+    table.add_column("Metric", style="cyan")
+    table.add_column("Score", justify="right")
+
+    if threshold is not None:
+        table.add_column("Status", justify="center")
+
+    for metric, score in sorted(results.items()):
+        score_str = f"{score:.4f}"
+
+        if threshold is not None:
+            status = "[green]PASS[/green]" if score >= threshold else "[red]FAIL[/red]"
+            table.add_row(metric, score_str, status)
+        else:
+            table.add_row(metric, score_str)
+
+    return table
+
+
+def format_validation_json(results: dict[str, float]) -> str:
+    """
+    Format validation results as JSON.
+
+    Args:
+        results: Dictionary of metric names to scores.
+
+    Returns:
+        JSON string.
+    """
+    return json.dumps(results, indent=2)
+
+
+def format_validation_simple(results: dict[str, float]) -> str:
+    """
+    Format validation results as simple text output.
+
+    Args:
+        results: Dictionary of metric names to scores.
+
+    Returns:
+        Simple text string with one metric per line.
+    """
+    lines = [f"{metric}: {score:.4f}" for metric, score in sorted(results.items())]
+    return "\n".join(lines)
+
+
+def format_benchmark_history(runs: list[BenchmarkRun]) -> Table:
+    """
+    Format benchmark run history as a Rich table.
+
+    Args:
+        runs: List of BenchmarkRun objects (most recent first).
+
+    Returns:
+        Rich Table object.
+    """
+    if not runs:
+        table = Table(title="Benchmark History")
+        table.add_column("No runs found")
+        return table
+
+    # Get all metric names from the runs
+    metric_names: set[str] = set()
+    for run in runs:
+        metric_names.update(run.metrics.keys())
+    sorted_metrics = sorted(metric_names)
+
+    table = Table(title="Benchmark History", show_header=True, header_style="bold")
+    table.add_column("Timestamp", style="cyan")
+    table.add_column("Samples", justify="right")
+    for metric in sorted_metrics:
+        table.add_column(metric, justify="right")
+
+    for run in runs:
+        timestamp = run.timestamp.strftime("%Y-%m-%d %H:%M")
+        samples = str(run.sample_count)
+        metric_values = [f"{run.metrics.get(m, 0.0):.4f}" for m in sorted_metrics]
+        table.add_row(timestamp, samples, *metric_values)
+
+    return table
+
+
+def format_regression_report(report: RegressionReport) -> Panel:
+    """
+    Format a regression report as a Rich panel.
+
+    Args:
+        report: RegressionReport object.
+
+    Returns:
+        Rich Panel object with formatted report.
+    """
+    if not report.detected:
+        content = (
+            f"[green]No regression detected.[/green]\nTolerance: {report.tolerance:.2%}"
+        )
+        return Panel(content, title="Regression Check", border_style="green")
+
+    # Build regression details
+    lines = [
+        "[red]Regression detected![/red]",
+        f"Tolerance: {report.tolerance:.2%}",
+        "",
+        "Metric details:",
+    ]
+
+    for metric in sorted(report.deltas.keys()):
+        baseline = report.baseline.get(metric, 0.0)
+        current = report.current.get(metric, 0.0)
+        delta = report.deltas[metric]
+
+        if delta < -report.tolerance:
+            status = "[red]REGRESSED[/red]"
+        else:
+            status = "[green]OK[/green]"
+
+        lines.append(
+            f"  {metric}: {current:.4f} (baseline: {baseline:.4f}, "
+            f"delta: {delta:+.4f}) {status}"
+        )
+
+    return Panel("\n".join(lines), title="Regression Check", border_style="red")
+
+
+def print_validation_output(
+    results: dict[str, float],
+    output_format: str = "table",
+    threshold: float | None = None,
+) -> None:
+    """
+    Print validation results in the specified format.
+
+    Args:
+        results: Dictionary of metric names to scores.
+        output_format: Output format ('table', 'json', or 'simple').
+        threshold: Optional threshold for pass/fail colouring (table only).
+    """
+    if output_format == "json":
+        console.print(format_validation_json(results))
+    elif output_format == "simple":
+        console.print(format_validation_simple(results))
+    else:
+        console.print(format_validation_table(results, threshold))