LLM 请求透明化

Co-authored-by: Copilot <copilot@github.com>

src/audit/llmRequestAudit.ts

@@ -0,0 +1,36 @@
+import { appendFile, mkdir } from "node:fs/promises";
+import { dirname } from "node:path";
+
+import { config } from "../config.js";
+
+export type LlmRequestAuditEntry = {
+  kind: "tool" | "skill";
+  sessionId: string;
+  clientSessionId: string;
+  traceId?: string;
+  projectId?: string;
+  target: string;
+  reason: string;
+  reasonProvided: boolean;
+  payload?: Record<string, unknown>;
+};
+
+let logDirectoryReadyPromise: Promise<void> | null = null;
+
+const ensureLogDirectory = async () => {
+  if (!logDirectoryReadyPromise) {
+    logDirectoryReadyPromise = mkdir(dirname(config.LLM_REQUEST_AUDIT_LOG_PATH), {
+      recursive: true,
+    }).then(() => undefined);
+  }
+  await logDirectoryReadyPromise;
+};
+
+export const writeLlmRequestAuditLog = async (entry: LlmRequestAuditEntry) => {
+  await ensureLogDirectory();
+  const line = JSON.stringify({
+    timestamp: new Date().toISOString(),
+    ...entry,
+  });
+  await appendFile(config.LLM_REQUEST_AUDIT_LOG_PATH, `${line}\n`, "utf8");
+};