docs: retire the criterion this version disproved, everywhere it survived

The reasoning_tokens docstring was still teaching downstream to treat
None or 0 as no reasoning. The changelog and the schema page had both
been corrected; the docstring had not, and it is the copy that ships in
the wheel and shows up on hover. Someone writing a report from it would
have counted every real MiniMax reasoning call as not reasoning, which
is issue #16 all over again with the tests green.

The original wording stays, since reading pre-1.3.1 rows still needs
it. What follows it now says when it expired and what to read instead.

Two more places had drifted the same way: the changelog and the
architecture doc described the throttle and the cache fallback as they
were before this review, which is to say as the opposite of what the
code now does.

The claim that the two throttle sets would suppress each other does not
survive checking, as the mutation testing showed: their key spaces do
not overlap. Keeping them apart is still right, but for the honest
reason, which is that the two warnings have unrelated lifetimes.

tests/integration/test_postgres_telemetry.py

@@ -949,10 +949,10 @@ class TestManualSchemaModeAcceptance:
     async def test_manual_leaves_the_stale_table_untouched(
         self, pre_tenant_schema, captured_warnings
     ):
-        """22 字段旧表 + manual: 列一个不加,行照常落库,缺的两维度静默不写。
+        """22 字段旧表 + manual: 列一个不加,行照常落库,缺的三维度静默不写。
 
         与 `test_pre_tenant_table_gains_columns_and_old_rows_stay_auditable` 恰成对照:
-        同一张表、同一份负载,只有 `auto_migrate` 不同,列数就必须是 23 与 25 之别。
+        同一张表、同一份负载,只有 `auto_migrate` 不同,列数就必须是 23 与 26 之别。
         """
         schema_dsn, schema = pre_tenant_schema
         recorder = _recorder(schema_dsn, auto_migrate=False)
@@ -981,7 +981,8 @@ class TestManualSchemaModeAcceptance:
             assert [m for m in captured_warnings if "补列失败" in m] == []
             notices = [m for m in captured_warnings if "auto_migrate=False" in m]
             assert len(notices) == 1  # 准备期一次讲清,不逐行刷屏
-            assert "以下维度不会被记录: tenant_id, meta" in notices[0]
+            # 逐字钉住三个维度: 前缀断言会让将来漏进告警的新列照样绿
+            assert "以下维度不会被记录: tenant_id, meta, thinking_observation。" in notices[0]
         finally:
             await recorder.aclose()
 
@@ -1007,7 +1008,8 @@ class TestManualSchemaModeAcceptance:
             assert recorder.telemetry_status.degraded is False
             notices = [m for m in captured_warnings if "auto_migrate=False" in m]
             assert len(notices) == 1  # 准备期一次,第二行不再重复
-            assert "以下维度不会被记录: tenant_id, meta" in notices[0]
+            # 逐字钉住三个维度: 前缀断言会让将来漏进告警的新列照样绿
+            assert "以下维度不会被记录: tenant_id, meta, thinking_observation。" in notices[0]
             # 提示里的 SQL 必须可直接粘贴执行,而不是只报个列名
             assert (
                 "ALTER TABLE llm_calls ADD COLUMN tenant_id TEXT NOT NULL DEFAULT '';" in notices[0]