fix(consult): drop traces, budget checkpoints, silent summary inherit

BUG-729: dropped history rounds leave an omission marker in the model-visible summary slot.
BUG-730: checkpoint threshold is 0.4 of historyBudgetChars (128k still 16,000).
BUG-731: session_full new chat copies owned context_summary on the server; clients send only continued_from_session_id.

frontend/tests/chat-session-authority.test.ts

@@ -20,6 +20,10 @@ test("session list GET omits messages while detail GET returns them", () => {
     /SESSION_LIST_COLUMNS = "id,title,theme,model_id,session_type,rectification_case_id,chart_profile_id,chart_profile_name,chart_profile_role,updated_at,pinned,archived_at"/,
   );
   assert.doesNotMatch(listRoute, /select\(SESSION_LIST_COLUMNS\)[\s\S]*messages/);
+  assert.doesNotMatch(
+    listRoute,
+    /SESSION_LIST_COLUMNS = "[^"]*context_summary/,
+  );
   assert.match(itemRoute, /export async function GET/);
   assert.match(
     itemRoute,
@@ -52,6 +56,8 @@ test("consult appends the user question after reserve and returns session_full",
   assert.match(sendSource, /caught\.code === "session_full"/);
   assert.match(sendSource, /label: "开新对话"/);
   assert.match(sendSource, /continueInNewChat\(\{ question: originalQuestion, theme \}\)/);
+  assert.match(page, /continuedFromSessionId: sourceSessionId/);
+  assert.doesNotMatch(page, /接着上次|继续上次聊|继承会话摘要|从上次对话继续/);
 });
 
 test("PATCH compatibility accepts and ignores a legacy messages write", () => {