docs: add JSDoc to all public API exports across client packages

Adds JSDoc comments to all undocumented public exports in davinci-client,
device-client, journey-client, and oidc-client. This eliminates
(undocumented) markers from API Extractor reports, improving the API
surface readability and enabling richer typedoc/IntelliSense output.

Author: ryanbas21

packages/davinci-client/api-report/davinci-client.api.md

@@ -13,13 +13,18 @@ import type {
 } from './collector.types.js';
 import type { ErrorNode, FailureNode, ContinueNode, StartNode, SuccessNode } from './node.types.js';
 
+/** Union of all possible DaVinci flow node states. */
 export type FlowNode = ContinueNode | ErrorNode | StartNode | SuccessNode | FailureNode;
 
+/** An error response generated internally by the SDK (not from the DaVinci API). */
 export interface InternalErrorResponse {
+  /** The error details including a human-readable message. */
   error: Omit<GenericError, 'error'> & { message: string };
+  /** The response type discriminant. */
   type: 'internal_error';
 }
 
+/** Function that initializes and starts a DaVinci flow, returning the first node or an error. */
 export type InitFlow = () => Promise<FlowNode | InternalErrorResponse>;
 
 /**
@@ -80,14 +85,20 @@ export type Updater<T = unknown> = (
   value: CollectorValueType<T>,
   index?: number,
 ) => InternalErrorResponse | null;
+/** Function that validates a collector value and returns validation errors or error details. */
 export type Validator = (value: string) =>
   | string[]
   | {
+      /** The validation error details. */
       error: {
+        /** The validation error message. */
         message: string;
+        /** The validation error type. */
         type: string;
       };
+      /** The validation result type. */
       type: string;
     };
 
+/** Union of all possible node states in a DaVinci flow lifecycle. */
 export type NodeStates = StartNode | ContinueNode | ErrorNode | SuccessNode | FailureNode;