🐛 fix(oceanbase): 修复 OceanBase 协议模式识别与缓存隔离

- 支持 MySQL/Oracle 租户协议在前后端统一解析
- 拒绝 Native 协议并避免误回退为 MySQL
- 修复 Oracle 模式下元数据、DDL、SQL 方言识别
- 修复连接缓存键与实际协议解析优先级不一致问题
- 补充前后端协议解析与缓存隔离回归测试

frontend/src/utils/oceanBaseProtocol.ts

@@ -0,0 +1,109 @@
+export type OceanBaseProtocol = 'mysql' | 'oracle';
+
+export const OCEANBASE_PROTOCOL_PARAM_KEYS = [
+  'protocol',
+  'oceanBaseProtocol',
+  'oceanbaseProtocol',
+  'tenantMode',
+  'compatMode',
+  'mode',
+];
+
+type OceanBaseProtocolResolution = {
+  protocol?: OceanBaseProtocol;
+  unsupportedValue?: string;
+  unsupportedKey?: string;
+};
+
+const normalizeToken = (value: unknown): string => String(value ?? '').trim().toLowerCase();
+
+export const normalizeOceanBaseProtocol = (value: unknown): OceanBaseProtocol | undefined => {
+  const normalized = normalizeToken(value);
+  if (!normalized) {
+    return undefined;
+  }
+  if (normalized === 'oracle' || normalized === 'oracle-mode' || normalized === 'oracle_mode' || normalized === 'oboracle') {
+    return 'oracle';
+  }
+  if (normalized === 'mysql' || normalized === 'mysql-compatible' || normalized === 'mysql_compatible' || normalized === 'mysql-mode' || normalized === 'mysql_mode' || normalized === 'obmysql') {
+    return 'mysql';
+  }
+  return undefined;
+};
+
+export const isUnsupportedOceanBaseProtocolValue = (value: unknown): boolean => {
+  const normalized = normalizeToken(value);
+  return normalized !== '' && !normalizeOceanBaseProtocol(normalized);
+};
+
+export const describeUnsupportedOceanBaseProtocol = (value: unknown): string => {
+  const raw = String(value ?? '').trim();
+  const label = raw ? ` "${raw}"` : '';
+  return `OceanBase 当前仅支持 MySQL/Oracle 租户协议，不支持${label}；请改为 MySQL 或 Oracle。`;
+};
+
+export const resolveOceanBaseProtocolFromQueryText = (raw: unknown): OceanBaseProtocolResolution => {
+  let text = String(raw ?? '').trim();
+  if (!text) {
+    return {};
+  }
+  const queryStart = text.indexOf('?');
+  if (queryStart >= 0) {
+    text = text.slice(queryStart + 1);
+  }
+  const hashStart = text.indexOf('#');
+  if (hashStart >= 0) {
+    text = text.slice(0, hashStart);
+  }
+  const params = new URLSearchParams(text.replace(/^[?&]+/, ''));
+  for (const key of OCEANBASE_PROTOCOL_PARAM_KEYS) {
+    const value = params.get(key);
+    if (value == null || String(value).trim() === '') {
+      continue;
+    }
+    const protocol = normalizeOceanBaseProtocol(value);
+    if (protocol) {
+      return { protocol };
+    }
+    return { unsupportedValue: value, unsupportedKey: key };
+  }
+  return {};
+};
+
+export const resolveOceanBaseProtocolFromConfig = (config: Record<string, unknown>): OceanBaseProtocol => {
+  const paramsProtocol = resolveOceanBaseProtocolFromQueryText(config.connectionParams);
+  const uriProtocol = resolveOceanBaseProtocolFromQueryText(config.uri);
+
+  if (Object.prototype.hasOwnProperty.call(config, 'oceanBaseProtocol')) {
+    const value = config.oceanBaseProtocol;
+    const protocol = normalizeOceanBaseProtocol(value);
+    if (isUnsupportedOceanBaseProtocolValue(value)) {
+      throw new Error(describeUnsupportedOceanBaseProtocol(value));
+    }
+    if (paramsProtocol.unsupportedValue) {
+      throw new Error(describeUnsupportedOceanBaseProtocol(paramsProtocol.unsupportedValue));
+    }
+    if (uriProtocol.unsupportedValue) {
+      throw new Error(describeUnsupportedOceanBaseProtocol(uriProtocol.unsupportedValue));
+    }
+    if (protocol) {
+      return protocol;
+    }
+  }
+
+  if (paramsProtocol.unsupportedValue) {
+    throw new Error(describeUnsupportedOceanBaseProtocol(paramsProtocol.unsupportedValue));
+  }
+  if (paramsProtocol.protocol) {
+    return paramsProtocol.protocol;
+  }
+
+  if (uriProtocol.unsupportedValue) {
+    throw new Error(describeUnsupportedOceanBaseProtocol(uriProtocol.unsupportedValue));
+  }
+  return uriProtocol.protocol || 'mysql';
+};
+
+export const resolveOceanBaseProtocolForDialect = (value: unknown): OceanBaseProtocol => (
+  normalizeOceanBaseProtocol(value) || 'mysql'
+);