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/chatPermissionPolicy.ts

@@ -0,0 +1,5 @@
+// Shell and file mutation remain interactive even when ordinary read-only
+// business tools are automatically approved. Static denials stay in OpenCode.
+export function canAutomaticallyApprove(mode: string, action: string) {
+  return mode === "always" && !["shell", "bash", "edit", "write", "patch", "read", "external_directory", "execute", "subagent"].includes(action);
+}