feat: add screencast state management to Context interface

Add getScreenRecorder/setScreenRecorder methods to the Context type and McpContext implementation. These store the active ScreenRecorder instance and its output file path, enabling start/stop screencast tool coordination.

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

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

Author: dobesv

src/McpContext.ts

@@ -26,6 +26,7 @@ import type {
   ElementHandle,
   HTTPRequest,
   Page,
+  ScreenRecorder,
   SerializedAXNode,
   PredefinedNetworkConditions,
   Viewport,
@@ -121,6 +122,8 @@ export class McpContext implements Context {
   #extensionRegistry = new ExtensionRegistry();
 
   #isRunningTrace = false;
+  #screenRecorderData: {recorder: ScreenRecorder; filePath: string} | null =
+    null;
   #networkConditionsMap = new WeakMap<Page, string>();
   #cpuThrottlingRateMap = new WeakMap<Page, number>();
   #geolocationMap = new WeakMap<Page, GeolocationOptions>();
@@ -372,6 +375,16 @@ export class McpContext implements Context {
     return this.#isRunningTrace;
   }
 
+  getScreenRecorder(): {recorder: ScreenRecorder; filePath: string} | null {
+    return this.#screenRecorderData;
+  }
+
+  setScreenRecorder(
+    data: {recorder: ScreenRecorder; filePath: string} | null,
+  ): void {
+    this.#screenRecorderData = data;
+  }
+
   isCruxEnabled(): boolean {
     return this.#options.performanceCrux;
   }

src/tools/ToolDefinition.ts

@@ -10,6 +10,7 @@ import type {
   Dialog,
   ElementHandle,
   Page,
+  ScreenRecorder,
   Viewport,
 } from '../third_party/index.js';
 import type {InsightName, TraceResult} from '../trace-processing/parse.js';
@@ -146,6 +147,10 @@ export type Context = Readonly<{
    * Returns a reqid for a cdpRequestId.
    */
   resolveCdpElementId(cdpBackendNodeId: number): string | undefined;
+  getScreenRecorder(): {recorder: ScreenRecorder; filePath: string} | null;
+  setScreenRecorder(
+    data: {recorder: ScreenRecorder; filePath: string} | null,
+  ): void;
   installExtension(path: string): Promise<string>;
   uninstallExtension(id: string): Promise<void>;
   listExtensions(): InstalledExtension[];