docs: plan the telemetry pool lifecycle rework for issue 15

The design traces the incident to four stacked defects rather than one bad
default: the pool is the only resource in the library that pre-allocates,
the kill switch keys off which step failed instead of what failed, the
degraded state can neither recover nor be observed, and the ownership rules
make the sanctioned sharing path unusable.

The plan sequences the tracker ahead of the pool and failure work so every
commit stays green, and records two facts the implementer needs up front:
the pool-construction path has zero test coverage today, and the commit
gate runs the full suite plus a complexity ceiling.

research-wiki/graph/edges.json

@@ -190,6 +190,16 @@
       "id": "review:issue14-branch-review",
       "label": "整分支审查: issue #14 熔断等待档",
       "type": "review"
+    },
+    {
+      "id": "design:issue15-telemetry-pool-lifecycle",
+      "label": "issue #15: 遥测连接池的资源语义与生命周期",
+      "type": "design"
+    },
+    {
+      "id": "plan:plan-issue15-telemetry-pool-lifecycle",
+      "label": "实现计划: 遥测连接池的资源语义与生命周期(issue #15)",
+      "type": "plan"
     }
   ],
   "links": [
@@ -353,6 +363,27 @@
       "relation": "informs",
       "evidence": "Important 项促使修正 CHANGELOG/README/设计 §4/计划 T5 对 wait 档失败 reason 的描述",
       "added": "2026-08-20T05:01:16.206639+00:00"
+    },
+    {
+      "source": "design:issue15-telemetry-pool-lifecycle",
+      "target": "design:issue9-telemetry-ddl-probe",
+      "relation": "refines",
+      "evidence": "把 issue #9 的'确定写不进去'判据从'哪一步失败'改为'失败是什么性质': 建池失败不再一律判死",
+      "added": "2026-08-24T05:50:56.787791+00:00"
+    },
+    {
+      "source": "design:issue15-telemetry-pool-lifecycle",
+      "target": "design:issue12-telemetry-retention",
+      "relation": "depends_on",
+      "evidence": "遥测作为审计证据的定位(决策 E-a)是否决'异步队列 + 后台 flush'备选的依据",
+      "added": "2026-08-24T05:50:57.954717+00:00"
+    },
+    {
+      "source": "plan:plan-issue15-telemetry-pool-lifecycle",
+      "target": "design:issue15-telemetry-pool-lifecycle",
+      "relation": "implements",
+      "evidence": "八任务实现四组改动(池语义/失败三分/状态可见/所有权纪律)",
+      "added": "2026-08-24T12:05:46.300738+00:00"
     }
   ]
 }