feat(core): add shared types, config validation, and error utilities

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-Claude)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/types/sage.ts

@@ -0,0 +1,82 @@
+export interface SageConfig {
+  url: string;
+  user: string;
+  password: string;
+  endpoint: string;
+  poolAlias: string;
+  language: string;
+  rejectUnauthorized: boolean;
+}
+
+export interface RestQueryOptions {
+  entity: string;
+  representation?: string;
+  where?: string;
+  orderBy?: string;
+  count?: number;
+  nextUrl?: string;
+  select?: string;
+}
+
+export interface RestQueryResult {
+  records: unknown[];
+  pagination: {
+    returned: number;
+    hasMore: boolean;
+    nextUrl?: string;
+  };
+}
+
+export interface RestDetailResult {
+  record: unknown;
+}
+
+export interface SoapCallContext {
+  codeLang: string;
+  poolAlias: string;
+  poolId: string;
+  requestConfig: string;
+}
+
+export interface SoapReadOptions {
+  publicName: string;
+  objectName?: string;
+  key: Record<string, string>;
+}
+
+export interface SoapQueryOptions {
+  publicName: string;
+  objectName?: string;
+  listSize?: number;
+  inputXml?: string;
+}
+
+export interface SoapResult {
+  status: number;
+  data: unknown;
+  messages: SoapMessage[];
+  technicalInfos: SoapTechInfo[];
+}
+
+export interface SoapMessage {
+  type: number;
+  message: string;
+}
+
+export interface SoapTechInfo {
+  type: string;
+  message: string;
+}
+
+export interface ToolResponse {
+  records?: unknown[];
+  record?: unknown;
+  pagination?: { returned: number; hasMore: boolean; nextUrl?: string };
+  error?: string;
+  hint?: string;
+}
+
+export interface HealthStatus {
+  rest: { status: string; latencyMs: number; endpoint: string };
+  soap: { status: string; latencyMs: number; poolAlias: string };
+}