feat(admin): 访客详情页按客迹视觉V1重设计（头部卡/统计卡/时间线/来源证据三口径/访问环境）

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

server/tracker/tests/test_visitors.py

@@ -176,15 +176,21 @@ def test_detail_shape(client, member_user):
     v = _visitor(site, "v1", screen="1920x1080", timezone_name="Asia/Shanghai",
                  last_ip="1.2.3.4", first_utm={"utm_source": "google"},
                  first_referrer_domain="google.com", first_landing_path="/landing")
-    _session(site, v, "s-old", at=NOW - timedelta(hours=2),
-             referrer_domain="google.com", stay_ms=60000, duration_ms=300000, event_count=3)
-    _session(site, v, "s-new", at=NOW, utm={"utm_source": "wechat"},
-             landing_path="/new", stay_ms=30000, duration_ms=120000, event_count=2)
+    s_old = _session(site, v, "s-old", at=NOW - timedelta(hours=2),
+                     referrer_domain="google.com", stay_ms=60000, duration_ms=300000,
+                     event_count=3)
+    s_new = _session(site, v, "s-new", at=NOW, utm={"utm_source": "wechat"},
+                     landing_path="/new", stay_ms=30000, duration_ms=120000, event_count=2)
+    _event(site, v, s_old, "e1", "page_view", NOW - timedelta(hours=2), path="/a")
+    _event(site, v, s_old, "e2", "page_stay", NOW - timedelta(minutes=119),
+           path="/a", active_ms=1000)
+    _event(site, v, s_new, "e3", "page_view", NOW, path="/b")
 
     r = client.get("/api/admin/visitors/v1")
     assert r.status_code == 200
     d = r.json()["data"]
     assert d["site_id"] == site.site_id and d["site_name"] == "s"   # 详情同样输出站点归属
+    assert d["pages_viewed"] == 2          # 只计 page_view；page_stay 是停留信号不并计
     assert d["screen"] == "1920x1080" and d["timezone_name"] == "Asia/Shanghai"
     assert d["last_ip"] == "1.2.3.4" and d["first_utm"] == {"utm_source": "google"}
     assert d["first_landing_path"] == "/landing" and d["first_referrer_domain"] == "google.com"
@@ -382,3 +388,44 @@ def test_detail_attribution_block(client, member_user):
     assert ft["computed_at"] and ft["detail"] == {}
     assert [e["session_id"] for e in attr["session_entries"]] == ["s2", "s1"]  # 最近在前
     assert attr["session_entries"][0]["channel"] == "ai_referral"
+
+
+def test_detail_source_evidence_triplet(client, member_user):
+    """三口径：首日 direct（不可识别）+ 次日 Google——first_observable=direct/unknown，
+    first_identifiable 回溯到次日的可识别会话入口，latest_session=最新会话入口。"""
+    _auth(client, member_user)
+    site = Site.objects.create(name="s", domains=["a.com"])
+    v = _visitor(site, "v1")
+    s1 = _session(site, v, "s1", at=NOW - timedelta(days=1))            # 首日直接访问
+    s2 = _session(site, v, "s2", at=NOW, referrer_domain="google.com")  # 次日 Google
+    _classify(site, v, "first_touch", "direct", resolution="unknown")
+    _classify(site, v, "session_entry", "direct", session=s1, resolution="unknown")
+    _classify(site, v, "session_entry", "natural_search", "Google", session=s2,
+              evidence_kind="observed_referrer", resolution="resolved")
+
+    r = client.get("/api/admin/visitors/v1")
+    assert r.status_code == 200
+    attr = r.json()["data"]["attribution"]
+    fo = attr["first_observable"]
+    assert fo["channel"] == "direct" and fo["resolution"] == "unknown"   # 首访可观测=直接
+    fi = attr["first_identifiable"]
+    assert fi["channel"] == "natural_search" and fi["platform"] == "Google"
+    assert fi["resolution"] == "resolved" and fi["session_id"] == "s2"   # 回溯到次日入口
+    ls = attr["latest_session"]
+    assert ls["channel"] == "natural_search" and ls["session_id"] == "s2"
+
+
+def test_detail_source_evidence_no_classification(client, member_user):
+    """历史数据无任何分类行：first_observable 给 unknown 占位，其余两口径为 null。"""
+    _auth(client, member_user)
+    site = Site.objects.create(name="s", domains=["a.com"])
+    v = _visitor(site, "v1")
+    _session(site, v, "s1", referrer_domain="google.com")
+
+    r = client.get("/api/admin/visitors/v1")
+    assert r.status_code == 200
+    attr = r.json()["data"]["attribution"]
+    assert attr["first_touch"] is None
+    assert attr["first_observable"] == {"channel": "unknown", "resolution": "unknown"}
+    assert attr["first_identifiable"] is None
+    assert attr["latest_session"] is None