Rewrite reviewed-finding localStorage hooks.

Dashboard count and report toggle still migrate legacy keys and skip the first persist write.

tests/test_periscope_frontend_reviewed_hooks_rewrite.py

@@ -0,0 +1,33 @@
+"""Reviewed-finding localStorage hooks live under periscope/src."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+SRC = ROOT / "periscope" / "src" / "frontend" / "src"
+
+
+def test_reviewed_hooks_are_src():
+    for rel in ("hooks/use-reviewed-count.ts", "hooks/use-reviewed-findings.ts"):
+        text = (SRC / rel).read_text(encoding="utf-8")
+        assert "Native Periscope overlay" not in text[:400]
+
+
+def test_reviewed_count_reads_migrated_key():
+    text = (SRC / "hooks/use-reviewed-count.ts").read_text(encoding="utf-8")
+    assert "export function useReviewedCount" in text
+    assert "reviewedFindingsKey" in text
+    assert "legacyReviewedFindingsKey" in text
+    assert "migrateLocalKey" in text
+
+
+def test_reviewed_findings_return_shape():
+    text = (SRC / "hooks/use-reviewed-findings.ts").read_text(encoding="utf-8")
+    assert "export function useReviewedFindings" in text
+    assert "toggleReviewed" in text
+    assert "isReviewed" in text
+    assert "reviewedCount" in text
+    assert "reviewedIds" in text
+    assert "getFindingKey" in text
+    assert "skipFirstWrite" in text or "hydrated" in text