replay ui fix (#56)

* refactor: rename inspect to replay across the codebase

Renames inspect-ui/ to replay-ui/, internal/inspect/ to internal/replay/,
the CLI subcommand from `sanderling inspect` to `sanderling replay`, and
updates all references in docs, Makefile, README, and Go comments.

* feat(replay-ui): show spec filename with full path on hover

RunList and RunDetail now render the basename of spec_path (e.g.
login.spec.ts) with the full path available as a title tooltip.

replay-ui/src/hooks/useStep.ts

@@ -0,0 +1,43 @@
+import { useEffect } from "react";
+import { useNavigate, useParams } from "react-router-dom";
+
+export interface UseStepResult {
+  runId: string;
+  stepIndex: number;
+  goTo: (index: number) => void;
+}
+
+export function useStep(maxIndex: number | undefined): UseStepResult {
+  const navigate = useNavigate();
+  const { id, step } = useParams<{ id: string; step: string }>();
+  const runId = id ?? "";
+  const parsed = Number(step ?? "1");
+  const stepIndex = Number.isFinite(parsed) && parsed > 0 ? parsed : 1;
+
+  const clamped = clampIndex(stepIndex, maxIndex);
+
+  useEffect(() => {
+    if (clamped !== stepIndex && runId !== "") {
+      navigate(`/runs/${runId}/steps/${clamped}`, { replace: true });
+    }
+  }, [clamped, stepIndex, runId, navigate]);
+
+  const goTo = (index: number) => {
+    const target = clampIndex(index, maxIndex);
+    if (target !== stepIndex && runId !== "") {
+      navigate(`/runs/${runId}/steps/${target}`);
+    }
+  };
+
+  return { runId, stepIndex: clamped, goTo };
+}
+
+function clampIndex(index: number, maxIndex: number | undefined): number {
+  if (index < 1) {
+    return 1;
+  }
+  if (maxIndex !== undefined && index > maxIndex) {
+    return maxIndex;
+  }
+  return index;
+}