feat(server): 业务事件契约——白名单+6事件与枚举校验

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

server/tracker/constants.py

@@ -1,6 +1,8 @@
 import re
 
-EVENT_NAMES = {"page_view", "page_stay", "sdk_loaded", "session_resume"}
+BIZ_EVENT_NAMES = {"contact_click", "form_start", "form_error", "form_submit",
+                   "form_submit_result", "product_view"}  # 阶段B业务事件（spec §1）
+EVENT_NAMES = {"page_view", "page_stay", "sdk_loaded", "session_resume"} | BIZ_EVENT_NAMES
 SCHEMA_VERSION = 2  # 批级信缺省 = v1（旧SDK）
 MAX_EVENTS_PER_BATCH = 50
 MAX_PROP_KEYS = 32
@@ -25,6 +27,13 @@ EVENT_PROP_WHITELIST = {          # spec §9.1：未知字段拒绝。免费文
     "page_stay": {"active_ms", "path", "active_from", "active_to", "flush_reason", "measurement_version"},
     "sdk_loaded": {"sdk_version", "build_id", "schema_version", "config_version"},
     "session_resume": {"prev_session_id", "reason"},
+    # 业务事件属性键白名单（spec §2）——值级枚举/格式校验在 validation._biz_props_ok
+    "contact_click": {"channel"},
+    "form_start": {"form_id"},
+    "form_submit": {"form_id", "submission_id"},
+    "form_error": {"form_id", "submission_id", "error_code", "field_count"},
+    "form_submit_result": {"form_id", "submission_id", "result_code"},
+    "product_view": {"product_id", "inferred", "rule_version"},
 }
 MAX_PROP_DEPTH = 2
 MAX_PROP_JSON_BYTES = 4096