feat(server): schema v2契约——session_resume白名单/Event归属与区间字段/会话resume_of/request_id

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

server/tracker/models.py

@@ -69,6 +69,8 @@ class VisitSession(models.Model):
     event_count = models.PositiveIntegerField(default=0)
     duration_ms = models.PositiveBigIntegerField(default=0)   # 会话内事件时间跨度
     stay_ms = models.PositiveBigIntegerField(default=0)       # 有效停留累计（page_stay active_ms 之和）
+    resume_of = models.ForeignKey("self", null=True, blank=True, on_delete=models.SET_NULL,
+                                  related_name="resumes")  # schema v2：session_resume 续接的前一会话（被指向会话删除后置 NULL 保留链）
 
     class Meta:
         db_table = "visit_session"
@@ -99,6 +101,14 @@ class Event(models.Model):
     city = models.CharField(max_length=64, blank=True, default="")
     late = models.BooleanField(default=False)
     is_bot = models.BooleanField(default=False)
+    # ---- schema v2（阶段A）：旧行空 = legacy ----
+    page_id = models.CharField(max_length=64, blank=True, default="", db_index=True)  # 埋点实例归属（spa 路由切换每页新 id）
+    active_from_ms = models.BigIntegerField(null=True, blank=True)   # 活跃区间起（页面时间戳 ms）
+    active_to_ms = models.BigIntegerField(null=True, blank=True)     # 活跃区间止
+    flush_reason = models.CharField(max_length=16, blank=True, default="")  # periodic/hidden/unload/interval等
+    time_quality = models.CharField(max_length=16, blank=True, default="")  # ok/adjusted/monotonic…（late 的补充细化）
+    sdk_version = models.CharField(max_length=16, blank=True, default="")
+    schema_version = models.PositiveSmallIntegerField(null=True, blank=True)  # 事件级信（缺省为批级/1）
 
     class Meta:
         db_table = "event"
@@ -128,6 +138,7 @@ class RawBatch(models.Model):
     status = models.CharField(max_length=16, default="accepted")  # accepted/partial/rejected
     received_at = models.DateTimeField(auto_now_add=True)
     ip = models.GenericIPAddressField(null=True, blank=True)
+    request_id = models.CharField(max_length=64, blank=True, default="")  # schema v2：批级请求标识（对账/去重排查）
 
     class Meta:
         db_table = "raw_batch"