feat: track logical call statistics across governed calls

tests/unit/test_embedding.py

@@ -600,3 +600,43 @@ class TestReasonlessTelemetryContract:
             assert seen == [{"model": "embed-1", "input": ["text"]}]
         finally:
             await transport.aclose()
+
+
+class TestEmbedLogicalCallStats:
+    """分批共享同一逻辑调用(1.3.5 设计 §3/§3.5)。"""
+
+    async def test_three_batches_count_three_attempts(self):
+        """分批是库的实现细节,但每批都真打了一次网关,故计 3 次尝试。"""
+        client, _ = _embed_client([_src()], ["ok", "ok", "ok"], batch_size=2)
+        resp = await client.embed(["a", "bb", "ccc", "dddd", "eeeee"])
+        assert resp.call_stats is not None
+        assert resp.call_stats.attempts == 3
+
+    async def test_separate_calls_get_distinct_logical_ids(self):
+        """一次公开调用一个 ID: 两次 `embed` 不得共用同一个。
+
+        共用就意味着上下文被提升成了 client 实例属性(库铁律禁止的形态)。
+        """
+        client, _ = _embed_client([_src()], ["ok"] * 5, batch_size=2)
+        first = await client.embed(["a", "bb", "ccc", "dddd", "eeeee"])  # 3 批
+        second = await client.embed(["x", "y"])  # 1 批
+        assert first.call_stats.attempts == 3 and second.call_stats.attempts == 1
+        assert first.call_stats.logical_call_id != second.call_stats.logical_call_id
+
+    async def test_retry_within_a_batch_is_counted(self):
+        client, _ = _embed_client([_src(), _src(name="e2")], [TransientError("t1"), "ok"])
+        resp = await client.embed(["a"])
+        assert resp.call_stats.attempts == 2
+
+    async def test_empty_input_is_zero_attempts_and_writes_no_telemetry_row(self):
+        """合法零尝试: 返回真实统计,且**不写任何遥测行**(设计 §3 M2)。
+
+        与 cache_hit 不同——不要按"遥测必录"推断空输入也有台账行。
+        """
+        rec = _MemoryRecorder()
+        client, _ = _embed_client([_src()], [], telemetry=rec)
+        resp = await client.embed([])
+        assert resp.call_stats is not None
+        assert resp.call_stats.attempts == 0
+        assert resp.call_stats.logical_call_id  # 真实 ID,不是空串
+        assert rec.rows == []  # 零遥测行