docs: v1.56 release notes (microsoft#37687)

Author: agg23

docs/src/release-notes-js.md

@@ -6,6 +6,65 @@ toc_max_heading_level: 2
 
 import LiteYouTube from '@site/src/components/LiteYouTube';
 
+## Version 1.56
+
+<LiteYouTube
+  id="_AifxZGxwuk"
+  title="Playwright 1.56 - Introducing Playwright Agents"
+/>
+
+### Playwright Agents
+
+Introducing Playwright Agents, three custom agent definitions designed to guide LLMs through the core process of building a Playwright test:
+
+* **🎭 planner** explores the app and produces a Markdown test plan
+
+* **🎭 generator** transforms the Markdown plan into the Playwright Test files
+
+* **🎭 healer** executes the test suite and automatically repairs failing tests
+
+Run `npx playwright init-agents` with your client of choice to generate the latest agent definitions:
+
+```bash
+# Generate agent files for each agentic loop
+# Visual Studio Code
+npx playwright init-agents --loop=vscode
+# Claude Code
+npx playwright init-agents --loop=claude
+# opencode
+npx playwright init-agents --loop=opencode
+```
+
+[Learn more about Playwright Agents](./test-agents.md)
+
+### New APIs
+
+- New methods [`method: Page.consoleMessages`] and [`method: Page.pageErrors`] for retrieving the most recent console messages from the page
+- New method [`method: Page.requests`] for retrieving the most recent network requests from the page
+- Added [`--test-list` and `--test-list-invert`](./test-cli.md#test-list) to allow manual specification of specific tests from a file
+
+### UI Mode and HTML Reporter
+
+- Added option to `'html'` reporter to disable the "Copy prompt" button
+- Added option to `'html'` reporter and UI Mode to merge files, collapsing test and describe blocks into a single unified list
+- Added option to UI Mode mirroring the `--update-snapshots` options
+- Added option to UI Mode to run only a single worker at a time
+
+### Breaking Changes
+
+- Event [`event: BrowserContext.backgroundPage`] has been deprecated and will not be emitted. Method [`method: BrowserContext.backgroundPages`] will return an empty list
+
+### Miscellaneous
+
+- Aria snapshots render and compare `input` `placeholder`
+- Added environment variable `PLAYWRIGHT_TEST` to Playwright worker processes to allow discriminating on testing status
+
+### Browser Versions
+
+- Chromium 141.0.7390.37
+- Mozilla Firefox 142.0.1
+- WebKit 26.0
+
 ## Version 1.55
 
 ### New APIs