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/src/app/api/consult/route.ts

@@ -330,6 +330,7 @@ export async function POST(request: Request) {
       { status: 503 },
     );
   }
+  const sessionContextWindow = sessionModel.contextWindow;
 
   if (parsed.data.entrypoint === "birth_time_rectification") {
     return NextResponse.json(
@@ -353,7 +354,7 @@ export async function POST(request: Request) {
   // Client `history` stays in the request schema for old bundles and is not read.
   const contextSummary = parseSessionContextSummary(chatSession.context_summary);
   const historyWindow = consultationHistoryWindow(chatSession.messages, contextSummary, {
-    contextWindow: sessionModel.contextWindow,
+    contextWindow: sessionContextWindow,
   });
   const storedHistory = historyWindow.tail;
   const userControlledPrompt = [
@@ -596,6 +597,7 @@ export async function POST(request: Request) {
       await checkpointSessionContextSummary({
         messages: sessionRow.messages,
         summary: sessionRow.context_summary,
+        contextWindow: sessionContextWindow,
         generateText: (prompt, signal) => generateSessionContextSummaryText(summaryModel, prompt, signal),
         update: async (summary, seenUpdatedAt) => {
           let query = supabase.from("chat_sessions")
@@ -875,6 +877,7 @@ export async function POST(request: Request) {
             instruction: modeInstruction,
             extra: generalDailyContextPrompt(generalDailyContext),
             summaryText: historyWindow.summaryText,
+            droppedCount: historyWindow.droppedCount,
             question: resolvedQuestion.modelQuestion,
           }),
         },
@@ -1271,6 +1274,7 @@ export async function POST(request: Request) {
           instruction: generalNoMinuteInstruction(Boolean(generalDailyContext)),
           extra: generalDailyContextPrompt(generalDailyContext),
           summaryText: historyWindow.summaryText,
+          droppedCount: historyWindow.droppedCount,
           question: resolvedQuestion.modelQuestion,
         }),
       },
@@ -1355,6 +1359,7 @@ export async function POST(request: Request) {
           name,
           instruction: "先用 3–6 句口语直接回答下面的问题，不要加标题；形状为一句结论、2–3 条短要点（每条完整句子、不超过 30 字）、一句下一步，总量不超过 400 字；然后再按 skill Level 2 骨架写：原始结构、六步宫位、Yoga 表、时机、综合、文末技法审计表，最后才是现代生活。骨架不可省略。星盘事实只使用系统里已经注入的计算结果，不要复述内部字段、JSON 或再跑一遍咨询流程。",
           summaryText: historyWindow.summaryText,
+          droppedCount: historyWindow.droppedCount,
           question: resolvedQuestion.modelQuestion,
         }),
       },
@@ -1379,6 +1384,7 @@ export async function POST(request: Request) {
             name,
             instruction: "先用 3–6 句口语直接回答下面的问题，不要加标题；形状为一句结论、2–3 条短要点（每条完整句子、不超过 30 字）、一句下一步，总量不超过 400 字；然后再按 skill Level 2 骨架写：原始结构、六步宫位、Yoga 表、时机、综合、文末技法审计表，最后才是现代生活。骨架不可省略。星盘事实只使用系统里已经注入的计算结果，不要复述内部字段、JSON 或再跑一遍咨询流程。",
             summaryText: historyWindow.summaryText,
+            droppedCount: historyWindow.droppedCount,
             question: resolvedQuestion.modelQuestion,
           }),
         },

frontend/src/app/api/sessions/route.ts

@@ -1,6 +1,12 @@
 import { NextResponse } from "next/server";
-import { chatSessionCreateSchema, ChatSessionBodyTooLargeError, readChatSessionJson } from "@/lib/chat-session-write-contract";
+import {
+  chatSessionCreateInsertRow,
+  chatSessionCreateSchema,
+  ChatSessionBodyTooLargeError,
+  readChatSessionJson,
+} from "@/lib/chat-session-write-contract";
 import { consumeUserRequestRateLimit } from "@/lib/request-rate-limit";
+import { resolveInheritedContextSummary } from "@/lib/session-context-summary";
 import { isSupabaseConfigurationError } from "@/lib/supabase/config";
 import { createServerSupabaseClient } from "@/lib/supabase/server";
 import {
@@ -94,13 +100,28 @@ export async function POST(request: Request) {
     }
     const parsed = chatSessionCreateSchema.safeParse(await readChatSessionJson(request));
     if (!parsed.success) return NextResponse.json({ error: "聊天记录格式不正确" }, { status: 400 });
-    const { id, updated_at: _ignoredClientClock, ...values } = parsed.data;
-    const { error } = await supabase.from("chat_sessions").insert({
-      id,
-      user_id: user.id,
-      ...values,
-      updated_at: new Date().toISOString(),
+    const { id, updated_at: _ignoredClientClock, continued_from_session_id: continuedFromSessionId, ...values } = parsed.data;
+    const inheritedSummary = await resolveInheritedContextSummary({
+      continuedFromSessionId,
+      loadOwnedSummary: async (sourceId) => {
+        const { data } = await supabase
+          .from("chat_sessions")
+          .select("context_summary")
+          .eq("id", sourceId)
+          .eq("user_id", user.id)
+          .maybeSingle();
+        return data?.context_summary ?? null;
+      },
     });
+    const { error } = await supabase.from("chat_sessions").insert(
+      chatSessionCreateInsertRow({
+        id,
+        userId: user.id,
+        values,
+        inheritedSummary,
+        updatedAt: new Date().toISOString(),
+      }),
+    );
     if (error) return NextResponse.json({ error: "聊天记录暂时无法同步" }, { status: 500 });
     return NextResponse.json({ ok: true }, { status: 201 });
   } catch (error) {