feat: 会商链条启停与深度研究报告结构，并完善问答展示与 8BF 返回。

Co-authored-by: Cursor <cursoragent@cursor.com>

offline-backend-20260512/backend/scripts/sql/column_additions_mysql.sql

@@ -94,6 +94,11 @@ CALL _add_column_if_missing('roundtable_chains', 'seat_mode', 'VARCHAR(16) NULL
 --               ORM: RoundtableChainRow.gather_first = Boolean, NOT NULL, server_default '0'。
 CALL _add_column_if_missing('roundtable_chains', 'gather_first', 'TINYINT(1) NOT NULL DEFAULT 0');
 
+-- enabled: 业务链条启停开关,对应 migration 20260819_02。True=启用(可选入研讨);
+--          False=停用(管理列表仍可见)。默认启用,存量行补列后也为 True。
+--          ORM: RoundtableChainRow.enabled = Boolean, NOT NULL, server_default '1'。
+CALL _add_column_if_missing('roundtable_chains', 'enabled', 'TINYINT(1) NOT NULL DEFAULT 1');
+
 -- ---- 岗位 (positions) 订阅系统,对应 migration 20260616_01 -------------------
 -- positions / position_tag_bindings 是【新表】,由 create_all 自动建,无需补列。
 -- 以下是给【已存在的表】补的列:
@@ -212,5 +217,6 @@ SELECT table_name, column_name
         OR (table_name = 'roundtable_jobs' AND column_name = 'task_id')
         OR (table_name = 'position_roundtable_sessions' AND column_name = 'task_scoped')
         OR (table_name = 'task_buttons' AND column_name IN ('append_auth', 'auth_token_param', 'auth_name_param'))
-        OR (table_name = 'compact_menu_overrides' AND column_name = 'menu_type'))
+        OR (table_name = 'compact_menu_overrides' AND column_name = 'menu_type')
+        OR (table_name = 'roundtable_chains' AND column_name = 'enabled'))
  ORDER BY table_name, column_name;