feat(v1): add event-log summary tool for acceptance evidence

v1/report.py reads events.jsonl and lists each confirmed event with its
latency (flags the 1-3s target) and screenshot, or reports a clean pass
when empty. Supports T-204 latency records and false-alarm counting.
78 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

v1/tests/test_report.py

@@ -0,0 +1,60 @@
+import json
+
+from v1.report import collect_jsonl, format_report, load_events, summarize
+
+
+def _write_events(path, events):
+    path.write_text(
+        "\n".join(json.dumps(e, ensure_ascii=False) for e in events) + "\n",
+        encoding="utf-8",
+    )
+
+
+def _event(event_id, latency):
+    return {
+        "event_id": event_id,
+        "track_id": "P-0001",
+        "confirmed_at_utc": "2026-07-21T08:30:00+00:00",
+        "latency_seconds": latency,
+        "screenshot": "20260721/{0}.png".format(event_id),
+    }
+
+
+def test_load_events_reads_each_jsonl_line(tmp_path):
+    jsonl = tmp_path / "events.jsonl"
+    _write_events(jsonl, [_event("FALL-A-000001", 1.8), _event("FALL-A-000002", 2.1)])
+
+    events = load_events(jsonl)
+
+    assert len(events) == 2
+    assert events[0]["event_id"] == "FALL-A-000001"
+
+
+def test_summarize_counts_latency_in_target_window(tmp_path):
+    events = [_event("a", 1.8), _event("b", 0.9), _event("c", 3.0)]
+
+    summary = summarize(events)
+
+    assert summary["count"] == 3
+    assert summary["latency_in_target"] == 2  # 1.8 and 3.0 are within 1-3s, 0.9 is not
+
+
+def test_empty_log_reads_as_clean_pass(tmp_path):
+    jsonl = tmp_path / "events.jsonl"
+    jsonl.write_text("", encoding="utf-8")
+
+    events = load_events(jsonl)
+    report = format_report(jsonl, events)
+
+    assert events == []
+    assert "no confirmed events" in report
+
+
+def test_collect_jsonl_finds_day_directories(tmp_path):
+    day = tmp_path / "20260721"
+    day.mkdir()
+    _write_events(day / "events.jsonl", [_event("FALL-A-000001", 1.8)])
+
+    found = collect_jsonl(tmp_path)
+
+    assert found == [day / "events.jsonl"]