fix: declare browser.setCustomTags on WebdriverIO.Browser type (SDK-6882)

.changeset/fix-sdk-6882-setcustomtags-type.md

@@ -0,0 +1,5 @@
+---
+"@wdio/browserstack-service": patch
+---
+
+Declare `browser.setCustomTags(key, value)` on the global `WebdriverIO.Browser` interface so TypeScript consumers can call it without a `TS2339` compile error. The command already worked at runtime; the declaration previously lived only in `src/@types/bstack-service-types.d.ts`, which is never emitted into the shipped `build/index.d.ts`. No runtime change.

packages/browserstack-service/src/index.ts

@@ -26,7 +26,8 @@ declare global {
             getAccessibilityResults: () => Promise<Array<Record<string, unknown>>>,
             performScan: () => Promise<Record<string, unknown> | undefined>,
             startA11yScanning: () => Promise<void>,
-            stopA11yScanning: () => Promise<void>
+            stopA11yScanning: () => Promise<void>,
+            setCustomTags: (key: string, value: string) => Promise<void>
         }
     }
     interface State {