fix(agent): preserve runtime request context

OpenCode tools run in a child service, so they cannot read the Agent process-local session map. Hydrate a sanitized context through the authenticated internal bridge and centralize backend project headers to prevent context loss across both boundaries.

src/server.ts

@@ -4,6 +4,7 @@ import cors from "cors";
 import express from "express";
 
 import { requireAgentAuth } from "./auth/agentAuth.js";
+import { buildBackendContextHeaders } from "./auth/backendContextHeaders.js";
 import { SessionTranscriptStore } from "./sessions/transcriptStore.js";
 import { ChatSessionBridge } from "./chat/sessionBridge.js";
 import { config } from "./config.js";
@@ -20,6 +21,7 @@ import {
 import { buildChatRouter } from "./routes/chat.js";
 import { buildAgentPublicRouter } from "./routes/publicApi.js";
 import { opencodeRuntime } from "./runtime/opencode.js";
+import { serializeRuntimeSessionContext } from "./runtime/internalSessionContextBridge.js";
 import {
   getRuntimeSessionContext,
   markRuntimeSessionAuthExpired,
@@ -43,7 +45,7 @@ const resultReferenceStore = new ResultReferenceStore();
 const resultReferenceResolver = new ResultReferenceResolver(resultReferenceStore);
 const internalToken = config.AGENT_INTERNAL_TOKEN ?? randomUUID();
 
-// 这个 token 只用于仍需服务端上下文的工具桥（store_render_ref）。
+// 这个 token 只用于 OpenCode 子进程回调本服务的内部工具桥。
 process.env.TJWATER_AGENT_INTERNAL_TOKEN = internalToken;
 
 app.use(cors());
@@ -72,6 +74,26 @@ app.get("/health", async (_req, res) => {
   }
 });
 
+app.post("/internal/tools/session-context", (req, res) => {
+  if (req.header("x-agent-internal-token") !== internalToken) {
+    res.status(403).json({ message: "forbidden" });
+    return;
+  }
+
+  const sessionId =
+    typeof req.body?.session_id === "string" ? req.body.session_id.trim() : "";
+  const context = sessionId ? getRuntimeSessionContext(sessionId) : null;
+  if (!context) {
+    res.status(404).json({
+      message: "session context not found",
+      detail: sessionId,
+    });
+    return;
+  }
+
+  res.json(serializeRuntimeSessionContext(context));
+});
+
 app.post("/internal/tools/tjwater-cli-call", async (req, res) => {
   if (req.header("x-agent-internal-token") !== internalToken) {
     res.status(403).json({ message: "forbidden" });
@@ -294,13 +316,7 @@ const callBackendJson = async (
   const controller = new AbortController();
   const timer = setTimeout(() => controller.abort(), config.TJWATER_API_TIMEOUT_MS);
   try {
-    const headers: Record<string, string> = {
-      Accept: "application/json",
-      "Content-Type": "application/json",
-    };
-    if (context.accessToken) {
-      headers.Authorization = `Bearer ${context.accessToken}`;
-    }
+    const headers = buildBackendContextHeaders(context);
     const response = await fetch(new URL(path, config.TJWATER_API_BASE_URL), {
       method: "POST",
       headers,