feat(server): 完成 P2 后端能力（支付幂等、委派回收、OCR异步、审计）

server/src/services/ocr/index.js

@@ -0,0 +1,22 @@
+const { runTencentVatOcr } = require("./tencent");
+
+function isOcrEnabledForType(config, ocrType) {
+  return config.ocrProvider === "tencent" && ocrType === "vat";
+}
+
+async function runOcrForInvoice({ config, ocrType, imageBase64 }) {
+  if (config.ocrProvider !== "tencent") {
+    throw new Error(`Unsupported OCR provider: ${config.ocrProvider}`);
+  }
+
+  if (ocrType !== "vat") {
+    throw new Error(`Unsupported OCR type: ${ocrType}`);
+  }
+
+  return runTencentVatOcr(config, imageBase64);
+}
+
+module.exports = {
+  isOcrEnabledForType,
+  runOcrForInvoice,
+};