fix: make XHR retry hook actually retry and keep ICC switch state in sync

.cursor/rules/jsdoc-comments.mdc

@@ -0,0 +1,35 @@
+---
+description: Prefer JSDoc block comments over line comments
+globs: "**/*.{js,jsx,ts,tsx,mjs,cjs}"
+alwaysApply: false
+---
+
+# Comment style
+
+Use JSDoc-style block comments (`/** */`) for explanatory comments in application and library source. Do not use `//` line comments for explanations.
+
+```js
+// ❌ BAD
+// Re-open the XHR and restore headers before retrying.
+request.open(method, url, true)
+
+// ✅ GOOD
+/** Re-open the XHR and restore headers before retrying. */
+request.open(method, url, true)
+```
+
+Multi-line:
+
+```js
+/**
+ * When Range is ignored, complete from the buffered body instead of
+ * appending — otherwise coordinates duplicate and the loop never ends.
+ */
+```
+
+Exceptions (keep `//`):
+- Tooling directives: `eslint-disable`, `@ts-expect-error`, `biome-ignore`, `prettier-ignore`
+- Temporarily commented-out code
+- Shebang lines
+
+Public APIs should still use proper JSDoc tags (`@param`, `@returns`, etc.) inside `/** */`.

CONTRIBUTING.md

@@ -37,6 +37,8 @@ The [pnpm](https://pnpm.io/) package manager is used to manage dependencies and
 
 Source code is linted and formatted using [Biome](https://biomejs.dev/). TypeScript is used with [strict type checking compiler options](https://www.typescriptlang.org/tsconfig#Strict_Type_Checking_Options_6173) enabled. Semicolons are not used at the end of statements (Biome uses `asNeeded`).
 
+Explanatory comments use JSDoc-style block comments (`/** … */`), not `//` line comments. Keep `//` only for tooling directives (`eslint-disable`, `@ts-expect-error`, `biome-ignore`), temporarily commented-out code, and shebang lines.
+
 Use the following commands to check and fix style:
 
     $ pnpm run lint        # check for issues

src/AppConfig.d.ts

@@ -9,6 +9,8 @@ export type DicomWebManagerErrorHandler = (
 export interface DICOMwebClientRequestHookMetadata {
   url: string
   method: string
+  /** Combined request headers from dicomweb-client (needed to re-apply after retry open()). */
+  headers?: Record<string, string>
 }
 
 export interface RetryRequestSettings {
@@ -17,7 +19,7 @@ export interface RetryRequestSettings {
   minTimeout?: number
   maxTimeout?: number
   randomize?: boolean
-  retryableStatusCodes: number[]
+  retryableStatusCodes?: number[]
 }
 
 export interface EvaluationSetting {