feat(agent): migrate OpenCode 2 runtime and sandbox tools

Upgrade the runtime and native plugin API to OpenCode 2.0.24. Restore
session-scoped learning, credential renewal, typed project queries and
controlled frontend actions from the legacy Agent.

Replace host Shell execution with an approved Landlock/seccomp executor
and persistent per-session workspaces. Add typed Bocha search and Tianditu
geocoding bridges using the owning session credential. Require a working
kernel sandbox before startup and persist workspace files in deployments.

Validation completed before this commit: TypeScript checks, 150 Bun tests,
Docker build and UID 10001 sandbox execution, native Shell approval and
session recovery. Tianditu succeeded; Bocha currently reports exhausted
account quota. Unrelated investigation-report contract work is excluded.

src/routes/chatInteractionRoutes.ts

@@ -1,7 +1,8 @@
+import { refreshSessionCredential } from "../product/credential-refresh.js";
 import { type Router } from "express";
 import { z } from "zod";
 
-import { getLocalAgentContext } from "../context/localContext.js";
+import { getLocalAgentContext, getTrustedProductCredential } from "../context/localContext.js";
 import { logger } from "../logger.js";
 import { type OpencodeRuntimeAdapter } from "../runtime/opencode.js";
 import { type SessionMetadataStore } from "../sessions/metadataStore.js";
@@ -72,6 +73,21 @@ export const registerChatInteractionRoutes = (
     sessionUiStateStore,
   }: RegisterInteractionRoutesOptions,
 ) => {
+  chatRouter.post("/session/:session_id/credentials", async (req, res) => {
+    const record = await sessionMetadataStore.get(getLocalAgentContext(req), req.params.session_id);
+    const credential = getTrustedProductCredential(req);
+    if (!record || !credential) { res.status(404).json({ message: "session not found" }); return; }
+    const run = activeRuns.get(record.sessionId);
+    const requestId = typeof req.body?.request_id === "string" ? req.body.request_id : undefined;
+    if (!run || run.status !== "running" || (!requestId && record.purpose !== "task_execution")) {
+      res.status(409).json({ message: "credential refresh is not pending" }); return;
+    }
+    if (!refreshSessionCredential(record.sessionId, credential, requestId)) {
+      res.status(409).json({ message: "credential refresh request does not match" }); return;
+    }
+    res.status(202).json({ accepted: true });
+  });
+
   chatRouter.post("/permission/:request_id/reply", async (req, res) => {
     const requestId = req.params.request_id?.trim();
     const parsed = permissionReplyPayloadSchema.safeParse(req.body);