feat(API-11): Route API calls through AgilitonAPI gateway

Add gateway-first pattern: when AGILITON_API_KEY is set, route all
external API calls through the gateway with X-API-Key auth. Falls back
to direct API access when gateway is unavailable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

node_modules/@modelcontextprotocol/sdk/dist/cjs/examples/client/simpleOAuthClientProvider.d.ts

@@ -0,0 +1,26 @@
+import { OAuthClientProvider } from '../../client/auth.js';
+import { OAuthClientInformationMixed, OAuthClientMetadata, OAuthTokens } from '../../shared/auth.js';
+/**
+ * In-memory OAuth client provider for demonstration purposes
+ * In production, you should persist tokens securely
+ */
+export declare class InMemoryOAuthClientProvider implements OAuthClientProvider {
+    private readonly _redirectUrl;
+    private readonly _clientMetadata;
+    readonly clientMetadataUrl?: string | undefined;
+    private _clientInformation?;
+    private _tokens?;
+    private _codeVerifier?;
+    constructor(_redirectUrl: string | URL, _clientMetadata: OAuthClientMetadata, onRedirect?: (url: URL) => void, clientMetadataUrl?: string | undefined);
+    private _onRedirect;
+    get redirectUrl(): string | URL;
+    get clientMetadata(): OAuthClientMetadata;
+    clientInformation(): OAuthClientInformationMixed | undefined;
+    saveClientInformation(clientInformation: OAuthClientInformationMixed): void;
+    tokens(): OAuthTokens | undefined;
+    saveTokens(tokens: OAuthTokens): void;
+    redirectToAuthorization(authorizationUrl: URL): void;
+    saveCodeVerifier(codeVerifier: string): void;
+    codeVerifier(): string;
+}
+//# sourceMappingURL=simpleOAuthClientProvider.d.ts.map